Imaging the Effects of Serotonin 2A Receptor Modulation on Synaptic Density in Treatment-resistant Depression (SYNVEST)
Phase: PHASE2
Conditions: Treatment Resistant Depression
Sponsor: Centre for Addiction and Mental Health

 
 
 
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Imaging the effects of serotonin 2A receptor 
modulation on synaptic density in treatment-
resistant depression (SYNVEST) 
 
Protocol Identifying Number: 052-2022 
Principal Investigator: Dr. Ishrat Husain 
Version Number:  6.0 
Version Date: December 18th, 2024 
 
 
 
 
 
 
 
 
 
 

 
 
 
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Sponsor: 
 
 
 
 
 
Principal Investigator: 
 
 
 
 
Centre for Addiction and Mental Health 
Centre for Complex Interventions 
1025 Queen Street West,  
Toronto, Ontario M6J 1H4 
416-535-8501 ext. 39412 
 
Dr. Ishrat Husain MBBS, MD (Res.), MRCPsych 
Centre for Addiction and Mental Health (CAMH) 
100 Stokes Street, Room 4285 
Toronto, Ontario M6J1H4 
416-535-8501 ext. 37838 
 
 
Funder: 
University of Toronto, Department of Psychiatry 
250 College Street, 8th Floor 
Toronto, Ontario M5T1R8 
416-970-6948 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
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Table of Contents 
 
STATEMENT OF COMPLIANCE ................................................................................................. 5 
LIST OF ABBREVIATIONS ........................................................................................................ 6 
CLINICAL TRIAL SUMMARY ..................................................................................................... 8 
1.0 INTRODUCTION...............................................................................................................11 
1.1 
BACKGROUND .............................................................................................................11 
1.2 
STUDY INTERVENTION ...................................................................................................12 
1.3 
PRECLINICAL DATA TO DATE...........................................................................................12 
1.4 
CLINICAL DATA TO DATE................................................................................................15 
1.5 
RISKS/BENEFITS..........................................................................................................17 
2.0 CLINICAL TRIAL OBJECTIVES .........................................................................................21 
2.1 
PRIMARY OBJECTIVE ....................................................................................................21 
2.2 
SECONDARY OBJECTIVE ................................................................................................22 
3.0 CLINICAL TRIAL DESIGN .................................................................................................22 
3.1 
OVERALL DESIGN ........................................................................................................22 
3.2 
PRIMARY ENDPOINTS....................................................................................................27 
3.3 
SECONDARY ENDPOINTS ..................................................... ERROR! BOOKMARK NOT DEFINED. 
4.0 PARTICIPANT SELECTION AND WITHDRAWAL ................................................................27 
4.1 
TARGET POPULATION ...................................................................................................27 
4.2 
PARTICIPANT RECRUITMENT AND SCREENING .....................................................................27 
4.3 
EQUITY, DIVERSITY AND INCLUSION CONSIDERATIONS ..........................................................30 
4.4 
ELIGIBILITY CRITERIA ....................................................................................................30 
4.4.1 
Inclusion Criteria ....................................................................................................30 
4.4.2 
Exclusion Criteria ...................................................................................................31 
4.5 
LIFESTYLE CONSIDERATIONS ..........................................................................................32 
4.6 
SCREEN FAILURES .......................................................................................................32 
4.7 
PARTICIPANT WITHDRAWAL CRITERIA ...............................................................................32 
4.7.1 
When and How to Withdraw Participants ...................................................................32 
4.7.2 
Follow-up for Withdrawn Participants ........................................................................33 
4.7.3 
Early Termination Visit……………………………………………………………………………..14 
4.7.4 
Participants who are lost to Follow-up……………………………………………………………15 
 
5.0 STUDY INTERVENTION ....................................................................................................34 
5.1 
DESCRIPTION..............................................................................................................34 
5.2 
TREATMENT REGIMEN...................................................................................................36 
5.3 
METHOD FOR ASSIGNING PARTICIPANTS TO TREATMENT GROUPS ...........................................37 
5.4 
ADMINISTRATION OF STUDY INTERVENTION ........................................................................37 
5.5 
PARTICIPANT COMPLIANCE MONITORING ...........................................................................38 
5.6 
CONCOMITANT THERAPY ...............................................................................................38 
5.7 
PACKAGING ................................................................................................................41 
5.8 
BLINDING OF STUDY INTERVENTION..................................................................................41 
5.9 
RECEIVING, STORAGE, DISPENSING AND RETURN................................................................42 
5.9.1 
Receipt of Study Intervention Supplies ......................................................................42 
5.9.2 
Storage ................................................................................................................42 
5.9.3 
Dispensing of Study Intervention ..............................................................................42 
5.9.4 
Return or Destruction of Study Intervention ................................................................43 

 
 
 
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6.0 RESEARCH PROCEDURES ..............................................................................................43 
6.1 
RESEARCH VISITS ........................................................................................................43 
6.2 
SCHEDULE OF EVENTS ..................................................................................................52 
7.0 STATISTICAL PLAN .........................................................................................................55 
7.1 
SAMPLE SIZE DETERMINATION ........................................................................................55 
7.2 
STATISTICAL METHODS .................................................................................................55 
8.0 SAFETY AND ADVERSE EVENTS .....................................................................................56 
8.1 
DEFINITIONS ...............................................................................................................56 
8.2 
RECORDING OF ADVERSE EVENTS ...................................................................................57 
8.3 
REPORTING OF SERIOUS ADVERSE EVENTS .......................................................................58 
8.3.1 
Investigator Reporting: Notifying the Sponsor .............................................................58 
8.3.2 
Investigator Reporting: Notifying the REB ..................................................................58 
8.3.3 
Sponsor Reporting of SUADRs: Notifying Health Canada .............................................58 
8.3.4 
Sponsor Reporting of SUADRs: Notifying Sites ...........................................................58 
8.4 
REPORTING OF DEVICE DEFICIENCIES...............................................................................58 
8.5 
SAFETY MANAGEMENT PLAN ..........................................................................................58 
8.6 
UNBLINDING PROCEDURES.............................................................................................60 
8.7 
DATA AND SAFETY MONITORING BOARD............................................................................60 
9.0 CLINICAL TRIAL DISCONTINUATION AND CLOSURE ........................................................60 
9.1 
CLINICAL TRIAL DISCONTINUATION ...................................................................................60 
10.0 DATA HANDLING AND RECORD KEEPING........................................................................60 
10.1 
SOURCE DOCUMENTS & CASE REPORT FORMS ..................................................................60 
10.2 
PROTOCOL DEVIATIONS ................................................................................................61 
10.3 
RECORD RETENTION ....................................................................................................61 
10.4 
CLINICAL TRIAL REGISTRATION .......................................................................................61 
11.0 STUDY MONITORING, AUDITING, AND INSPECTING..........................................................61 
11.1 
STUDY MONITORING PLAN .............................................................................................61 
11.2 
AUDITING AND INSPECTING.............................................................................................61 
12.0 ETHICAL CONSIDERATIONS ............................................................................................62 
12.1 
RESEARCH ETHICS BOARD (REB) APPROVAL.....................................................................62 
12.2 
INFORMED CONSENT PROCESS & DOCUMENTATION .............................................................62 
13.0 PRIVACY AND CONFIDENTIALITY ....................................................................................63 
14.0 CLINICAL TRIAL FINANCES .............................................................................................64 
14.1 
FUNDING SOURCE........................................................................................................64 
14.2 
CONFLICT OF INTEREST .................................................................................................64 
15.0 PUBLICATION POLICY/DATA SHARING ............................................................................64 
15.1 
FUTURE SECONDARY USE OF DATA .................................................................................65 
16.0 REFERENCES .................................................................................................................65 

 
 
 
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STATEMENT OF COMPLIANCE 
 
This clinical trial will be carried out in accordance with the following:  
• International Conference on Harmonisation Good Clinical Practice (ICH GCP) 
• Tri-Council Policy Statement 2018 (TCPS 2) 
• ISO 14155:2020 for Medical Device Clinical Trials 
• Personal Health Information Protection Act (PHIPA), 2004; Chapter 3 Schedule A 
(PHIPA) and applicable regulations 
• Food and Drugs Act  
o Part C, Division 5 of the Food and Drug Regulations 
• Institutional and REB policies and procedures 
 
 
 
 
 
 
________________________________  
_____________________________ 
Signature of PI 
 
 
 
 
Date 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
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LIST OF ABBREVIATIONS 
AE 
 
Adverse Event 
ALT 
 
Alanine aminotransferase 
AST  
Aspartate aminotransferase 
ATHF  
Antidepressant Treatment History Form 
CAMH 
Center for Addiction and Mental Health 
CGI 
 
Clinical Global Impression Scale 
CRF   
Case report form(s) 
C-SSRS 
Columbia-Suicide Severity Rating Scale 
DMT  
5-Hydroxytryptamine 
ECG 
Electrocardiography 
ECT 
Electroconvulsive therapy 
EDI 
Equity, diversity, and inclusion 
GAD-7 
Generalized Anxiety Disorder 7-Item Scale 
HamD-17 
Hamilton Depression Rating Scale 
HDPE  
High-density polyethylene 
HIPPD  
Hallucinogen-induced persistent perceptual disorder 
HPMC 
Hydroxypropyl methyl cellulose 
GCP   
Good Clinical Practice 
ICF  
 
Informed consent form 
IP 
 
Investigational product 
IPAC  
Infection prevention and control 
LSD   
Lysergic acid diethylamide  

 
 
 
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MADRS 
Mongomery-Åsberg Depression Rating Scale 
MDD  
Major depressive disorder 
MDE  
Major depressive episode 
PAP  
Psilocybin-Assisted Psychotherapy 
PHI 
 
Personal Health Information 
PHIPA 
Personal Health Information Protection Act 
PI 
 
Principal Investigator 
QI 
 
Qualified Investigator 
RCT  
Randomized controlled trial 
REB  
Research ethics board 
SAE  
Serious Adverse Event 
SCID-5 
Structured Clinical Interview for DSM-5 
SETS  
Stanford Expectations of Treatment Scale 
SHAPS 
Snaith-Hamilton Pleasure Scale 
SSRI  
Selective Serotonin Reuptake Inhibitor 
SUSAR  
Suspected unexpected serious adverse reaction 
TASS  
Transcranial Magnetic Stimulation Adult Safety Screen 
TCPS 2 
Tri-Council Policy Statement  
TRD  
Treatment Resistant Depression 
WEMWS 
Warwick-Edinburgh Mental Wellbeing Scale 
WHO-QoL-BREF 
World Health Organization Quality of Life Questionnaire – Brief 
Version 
5D-ASC 
Five Dimensions of Altered States of Consciousness 

 
 
 
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CLINICAL TRIAL SUMMARY 
 
Title 
Imaging the effects of serotonin 2A receptor modulation on synaptic density in 
treatment-resistant depression (SYNVEST) 
 
Short Title 
SYNVEST 
Phase 
Phase I 
Methodology 
Open-label clinical trial 
Clinical trial Duration 
18-months to complete all recruitment, study procedures, and data analysis.  
Participating site(s) 
Single-Centre 

 
 
 
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Objectives 
To evaluate the feasibility and safety of obtaining PET imaging scans before and after 
administration of psilocybin (25 mg) with and without risperidone (1 mg) in adults with 
TRD.  
 
To obtain preliminary data on synaptic density (as measured by [18F] SynVesT-1 
volume distribution, VT) in brain regions relevant to MDD (i.e., prefrontal cortex) before 
and 4 weeks after psilocybin 25 mg vs psilocybin 25 mg plus risperidone 1 mg  in 
adults with TRD. 
 
To obtain preliminary data on cortical plasticity, as measured by TMS-EEG and resting 
EEG in brain regions relevant to MDD (i.e., prefrontal cortex) before, during and after 
psilocybin 25 mg vs psilocybin 25 mg plus risperidone 1 mg in adults with TRD. 
 
To obtain preliminary data on antidepressant effects as measured by the change in 
the MADRS from Baseline (V2) to 1-week post-treatment (V5). Antidepressant effects 
will also be measured at Weeks 2 (V6), 3 (V7), and 4 (V8) post-intervention. Response 
will be defined as a reduction of 50% or more of the MADRS score and remission 
defined as a score of <7 on the MADRS from Baseline (V1) to Week 1 (V5). 
 
Number of Participants 
Twelve participants diagnosed with treatment-resistant depression 
Study Intervention 
Reference 
Therapy/Comparator 
1 mg of risperidone in combination with 25mg of psilocybin taken in conjunction with 
psilocybin-assisted psychotherapy (PAP) or  25 mg of psilocybin alone taken in 
conjunction with PAP 
Duration of Intervention 
One day: 5-6 hours  

 
 
 
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Statistical Methodology 
Characteristics of the trial cohort will be summarized by mean (SD), median 
(minimum, maximum). Summary raw scores will be presented at each assessment 
time both numerically and graphically. The small sample size means that 
conservative nonparametric testing is required in order to address the primary and 
secondary objectives. Exact paired permutation t-tests will be used to determine 
whether psilocybin-assisted psychotherapy with or without risperidone achieves a 
50% reduction in MADRS. 
 

 
 
 
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1.0 INTRODUCTION 
1.1 
Background 
Treatment-Resistant Depression (TRD) affects up to a third of all depressed individuals (Wiles et al., 2013). Major 
depressive disorder (MDD) is a leading cause of disability worldwide. Although depressive symptoms are amenable to 
pharmacotherapy, a high proportion of patients experience TRD, typically defined as not responding to two or more 
adequate antidepressant trials, or relapse during treatment (Gaynes et al., 2020; Rush et al., 2006). TRD is associated 
with a significant decline in social and occupational functioning and higher rates of death by suicide and all-cause mortality 
(Reutfors et al., 2018). Persistent symptoms in TRD often translate into substantial increases in work loss, healthcare 
resource utilization, and costs, compared to more responsive forms of illness (Li et al., 2020). Current pharmacotherapy 
for TRD, including augmentation of antidepressants with atypical antipsychotics, lithium, or ketamine have high rates of 
non-response (Carter et al., 2020) and can be associated with problematic adverse effects (e.g., sedation, weight gain, 
diabetes, tardive dyskinesia) leading to non-adherence (Ho et al., 2017). Electroconvulsive therapy (ECT) is the most 
efficacious intervention for TRD. However, many patients with TRD refuse ECT because of stigma, lack of access, and 
fears of cognitive adverse effects (Wilkinson et al., 2021).  Transcranial magnetic stimulation (rTMS) is an alternative to 
ECT but its response and remission rates are similar to pharmacotherapy (Carter et al., 2020), leaving a large proportion 
of patients with TRD in need of novel interventions. 
 
Effects of Psilocybin on Synaptic Density  
 
Some evidence suggests that psychedelic drugs such as psilocybin promote growth and plasticity of synapses in the 
brain. These changes in neuronal connections are a potential mechanism for the clinical efficacy of psilocybin in treating 
major depressive disorder (MDD). Recent advances have allowed quantitative imaging of synaptic density in the living 
human brain to be performed for the first time using positron emission tomography (PET) with radiotracers selective for 
the synaptic vesicle glycoprotein 2A (SV2A). Using SV2A PET, synaptic density changes have been identified across a 
range of neurodegenerative and psychiatric disorders including MDD. This method may offer a way to measure 
synaptic density changes associated with treatment directly in patients. The goal of this study is to assess synaptic 
density before and after treatment with psilocybin in patients with treatment-resistant depression (TRD) in order to 
determine whether psilocybin induces measurable synapse (re)growth.  
 

 
 
 
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1.2 
Study Intervention 
Recently, psilocybin-assisted psychotherapy (PAP) has been gaining traction as a promising potential treatment for many 
mental illnesses, including end-of-life anxiety and treatment-resistant depression (Perkins et al., 2021). PAP procedures 
typically involve psychological preparation prior to therapist-supported psilocybin dosing sessions. These sessions are 
used to establish a therapeutic relationship, inform participants about what to expect, and set expectations for the dosing 
session. During the psilocybin dosing session, trained therapists support the individual through their experience and 
psychological integration therapy occurs after the dosing experience. Evidence from recent clinical trials suggest that 
PAP can help in the reduction of anxiety, depression, and substance use (Carhart-Harris et al., 2021; Griffiths et al., 2016; 
Grob et al., 2011; Ross et al., 2016).  With proper screening and preparation, psilocybin has a safe physiological and 
psychological profile.  
 
Psilocybin is a chemical compound that naturally occurs in certain species of mushrooms, (for example, in the psilocybe 
genus, among others). It belongs to a class of drugs referred to as ‘psychedelics’. Psilocybin is a tryptamine which is 
chemically similar to the neurotransmitter, serotonin, and the essential amino acid, tryptophan. It is considered a 5-
hydroxytrptamineric (serotonergic) psychedelic along with other similar drugs such as dimethyltryptamine (DMT) and 
lysergic acid dieythamide (LSD). Psilocybin is a prodrug for the pharmacologically active ingredient psilocin, which readily 
crosses the blood-brain barrier and acts as a potential partial agonist at serotonin 5HT2A and 5HT2c receptors in the brain 
(Halberstadt et al., 2011; Madsen et al., 2019). Typical effects of psilocybin include significantly altered states of 
consciousness, experienced through visual and sometimes auditory effects, changes in perception, distortions of time, 
and a range of effects including a sense of awe, novel perspectives, existential and personal insight, dramatically 
heightened empathy and feelings of compassion, strong emotions, and unitive experience. These mystical experiences 
are correlated with improvements in mood in healthy volunteers and palliative patients with end-of-life distress (Johnson 
et al., 2019). However, there is no convincing evidence that these psychedelic effects are required for an antidepressant 
effect in patients with MDD (Johnson et al., 2019). In fact, in a recent study, 24 participants who received PAP for MDD, 
showed no associations between psychedelic effects and sustained improvement in depressive symptoms, suggesting 
that psychedelic effects may not be necessary to harness psilocybin’s antidepressant effects (Gukasyan et al., 2022).  
 
In its current form, psilocybin is not suitable for wide scale clinical adoption. Despite published safety data, psilocybin-
induced alterations in perception and consciousness remain a major barrier to widespread clinical implementation, 
necessitating an 8-hour session of intensive psychological support in a clinical setting during administration, in addition 
to several lengthy preparation and integration sessions pre- and post-dosing. This complex process could be greatly 
simplified if the psychedelic effects could be diminished without impairing the antidepressant effects. In humans, the 
intensity of psilocybin-induced perceptual changes correlates with 5-HT2A activation (Madsen et al., 1995). However, 

 
 
 
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psilocybin’s antidepressant effects may be mediated through rapid activation of other critical 5-HT receptors. Two 5-
HT2A-receptor antagonists – risperidone (an atypical antipsychotic) and ketanserin (an antihypertensive) – eliminate self-
reported psilocybin psychedelic effects in humans (Vollenweider et al., 1998). Thus, this intervention will involve the 
administration of risperidone followed by PAP to determine if the psychedelic experience of psilocybin is necessary to 
produce antidepressant effects. 
 
Psilocybin effects on synaptic plasticity 
 
Like many other antidepressants, psilocybin is theorized to exert its therapeutic effects by stimulating synaptic plasticity 
in brain areas relevant to MDD including prefrontal cortex and hippocampus (Duman et al., 2016). Preclinical and in 
vitro evidence demonstrates that psilocybin and other psychedelic drugs induce increased synaptogenesis and growth 
of dendritic spines in neurons within the prefrontal cortex (de la Fuente Revenga et al., 2021; Ly et al., 2018; Shao et 
al., 2021) as well as neurogenesis within the hippocampus (Catlow et al., 2013; Lima da Cruz et al., 2018; Morales-
Garcia et al., 2020). However, to date direct evidence of this mechanism in humans is limited and challenging to come 
by.  
 
Our understanding of the neuroplastic effects of psilocybin in humans and their potential role in therapeutic efficacy 
remains incomplete. To date, no study has evaluated psilocybin effects on neuronal growth in humans and no 
study has evaluated psilocybin effects on synaptic density in vivo in any species. 
 
1.3 
Preclinical Data to Date 
Animal studies looking into the effects of psychedelics in rodents have found evidence for improvements in behavioral 
outcomes, assessed by measures of coping strategy and cognitive function. The long-term effects using LSD 
(Buchborn et al., 2014; Hibicke et al., 2020), psilocin (Horsley et al., 2018), psilocybin (Hibicke et al., 2020), and DMT 
(Cameron et al., 2019; Cameron et al., 2018) were comparable to traditional treatment antidepressants. Moreover, 
there is evidence suggesting improvements in dimensions of cognitive function, such as enhanced associative learning 
(Buchborn et al., 2014; Harvey, 2003) which are commonly impaired in major depressive disorder (Castaneda et al., 
2008). In vitro studies with rat brain preparations have demonstrated that risperidone has a 10-20 fold greater affinity for 
the 5-HT2A receptor than for the D2 receptor (Meltzer et al., 1989). Similarly, psilocybin also has a high affinity for the 5-
HT2A receptor. The intensity of psilocybin-induced perceptual changes is correlated with serotonin 2A receptor (5-
HT2AR) activation (Madsen et al., 2019). In a study involving 8-week old mice exposed to a chronic multimodal stress 
paradigm, hedonic state was assayed with an appetize choice task: a two-bottle sucrose preference test comparing 

 
 
 
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consumption of a 1% sucrose solution and water (Hesselgrave et al., 2021). Psilocybin injections restored preference 
for sucrose solution whereas mice given a saline injection retained low sucrose (Hesselgrave et al., 2021). In the 
second part of the study, researchers pre-treated the mice with a 5-HT2A/2C antagonist prior to the psilocybin or saline 
injection. The results indicated that the behavioural responses to the sucrose test were not prevented when the 
antagonist was administered (Hesselgrave et al., 2021). These results indicate that psilocybin’s antidepressant 
mechanism of action may not be dependent on the psychedelic effects (Hesselgrave et al., 2021).  
 
Psilocybin Effects on Synaptic Plasticity 
 
In preclinical models, psilocybin treatment has been shown to increase a range of markers of neuronal plasticity. In 
mice, a single dose of psilocybin induced rapid changes in gene transcription in the prefrontal cortex, activating 
pathways involved in cognition, neural growth, and plasticity (Fadahunsi et al., 2022). Similarly, in rats, a single dose of 
psilocybin increased expression of neuroplasticity-associated genes and proteins in prefrontal cortex and hippocampus 
(Jefsen et al., 2021). Another recent study examined the effect of psilocybin on synaptic protein density post mortem in 
pigs using autoradiography with [3H]UCB-J, a radioligand selective for the ubiquitous synaptic vesicle protein SV2A 
(Raval et al., 2021). This work found increased SV2A binding (synaptic density) 7 days after psilocybin administration in 
prefrontal cortex (+6.1%) and hippocampus (+9.2%).  
 
Role of 5-HT2A activation 
 
The intensity of psilocybin-induced perceptual changes (psychedelic effects) correlates with 5-HT2A activation (Madsen 
et al., 1995), but there is limited evidence that psychedelic effects are required for an antidepressant effect in patients 
with MDD (Johnson et al., 2019). Similarly, it is not yet clear whether 5-HT2A activation is necessary for the 
synaptogenic effects of psychedelic drugs. Psilocybin’s antidepressant effects may be mediated through other 
pathways, such as rapid activation of other critical 5-HT receptors. Specific blockade of 5-HT2A receptors with drugs 
such as risperidone and ketanserin can reduce expression of neurotrophic proteins and neurogenesis on their own in 
rodents (Catlow et al., 2013; Jiang et al., 2016; Vaidya et al., 1997). However, studies examining effects of 5-HT2A 
blockade on psilocybin-induced plasticity have produced mixed results (Ly et al., 2018; Shao et al., 2021). Presynaptic 
effects in particular have not been thoroughly investigated, though a recent study in mice found no effect of 5-HT2A pre-
block on the synaptic strengthening effects of psilocybin (Hesselgrave et al., 2021). Together this suggests that 
psilocybin may activate brain plasticity in part through 5-HT2A-independent mechanisms. 
 
PET Imagining of Synaptic Density 

 
 
 
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Studies in preclinical models have demonstrated sensitivity of SV2A PET to treatment-related changes in synaptic 
density, notably in mouse models of Alzheimer’s disease (Spurrier et al., 2022; Toyonaga et al., 2019). In humans, one 
pilot study found that in patients with MDD who showed pre-treatment synaptic density deficits, SV2A PET binding was 
significantly increased following a subanesthetic dose of ketamine, another drug through to exert antidepressant effects 
in part by stimulating synaptic plasticity. Further, this increase was associated with symptom improvement (Holmes et 
al., 2022). This provides highly preliminary but intriguing evidence that SV2A PET may provide a clinically-relevant 
measure of the neuroplastic effects of novel antidepressants. Notably, that pilot study used a single dose of ketamine 
rather than a typical multi-dose regimen used in treatment of MDD, and so may have underestimated the relevant 
effect. 
 
1.4 
Clinical Data to Date 
To date, there are numerous studies supporting the clinical efficacy of PAP for the treatment of depression and end-of-
life anxiety (Carhart-Harris et al., 2021; Griffiths et al., 2016; Ross et al., 2016). Currently, there are over 60 studies 
registered on ClinicalTrials.gov exploring the use of psilocybin to treat various mental health disorders. Several trials have 
observed rapid and sustained improvements in patients with treatment-resistant depression with one RCT demonstrating 
similar efficacy between psilocybin compared with an SSRI. Interestingly, secondary outcomes favoured psilocybin 
(Carhart-Harris et al., 2021). In particular, psilocybin, the chemical component of “magic mushrooms” at doses of 20-30 
mg, in conjunction with supportive psychotherapy, has shown large and sustained antidepressant effects in patients with 
MDD and TRD in contemporary open-label and randomized clinical trials (RCTs) (Carhart-Harris et al., 2021; Carhart-
Harris et al., 2016; Davis et al., 2021). For instance, in an open-label trial of psilocybin-assisted psychotherapy (PAP), 
63% of 19 participants with TRD responded 1 week after treatment, and 32% were not on any antidepressant or therapy 
for a further year (Carhart-Harris et al., 2016). Similarly, an RCT of 24 participants with MDD showed large effect sizes 
for PAP at week 1 (Cohen d = 2.5) and week 4 (Cohen d = 2.6) post-treatment compared with waitlist control (Davis et 
al., 2021). A long-term follow-up study of the same participants showed response and remission rates of 75% and 58%, 
respectively, at 12 months (Gukasyan et al., 2022). More recently, a trial comparing PAP with escitalopram in 59 
participants with non-refractory MDD showed that PAP was as effective as escitalopram in reducing depressive symptoms 
with no differences in adverse effects between groups (Carhart-Harris et al., 2016). Recently, an international phase II 
RCT of PAP for 233 patients with TRD was completed. Preliminary findings indicate that psilocybin 25 mg led to a 
significant reduction in scores on the Montgomery-Abserg Depression Rating Scale (MADRS) for at least 6 weeks post-
treatment, compared to psilocybin 1 mg (an active placebo), without significant differences in serious adverse events 
between groups (COMPASS, 2021).  

 
 
 
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Psilocybin Effects on Synaptic Plasticity 
 
Neuroimaging studies in humans using functional magnetic resonance imaging (fMRI) offer indirect support for an effect 
of psilocybin to promote brain plasticity. Whole-brain functional connectivity between brain regions is persistently 
increased following a single psilocybin dose in healthy humans (Barrett et al., 2020). Another study found that functional 
connectivity changes are related to symptom improvement post-psilocybin in TRD (Carhart-Harris et al., 2017). Because 
synaptic deficits are directly associated with functional connectivity deficits in depression (Holmes et al., 2019), synaptic 
density increases may be a correlate of this widespread increase in brain connectivity 
 
PET imaging of synaptic density 
 
PET imaging using SV2A-selective radiotracers [11C]UCB-J and [18F]SynVesT-1 (also known as [18F]SynVesT-1) has 
recently been developed as a method to measure synaptic vesicle density in vivo in the human brain (Finnema et al., 
2016). SV2A is a vesicle membrane protein expressed at constant levels in virtually all synapses. SV2A PET binding 
has been validated as a stable measure of synaptic density (Smart et al., 2021). In non-human primates, in vivo SV2A 
binding measures derived from PET correlate closely with ex vivo protein density of SV2A and synaptophysin (Finnema 
et al., 2016; Smart et al., 2021). A growing body of clinical literature has demonstrated that SV2A PET measures are 
sensitive to synapse loss in neuropsychiatric disorders, including Alzheimer’s disease, epilepsy, schizophrenia, 
cannabis use disorder, and post-traumatic stress disorder (Angarita et al., 2021; Chen et al., 2018; D'Souza et al., 2021; 
Finnema et al., 2020; Holmes et al., 2019; Matuskey et al., 2020; Onwordi et al., 2021). Most notably for the present 
work, one SV2A PET imaging study found that lower synaptic density in several brain areas implicated in mood, 
including dorsolateral prefrontal cortex, anterior cingulate cortex, and hippocampus, is associated worse depressive 
symptoms in unmedicated patients (Holmes et al., 2019). Each of these brain regions has been previously identified as 
a site of synaptic, structural, or functional changes following psilocybin treatment (Fadahunsi et al., 2022; Jefsen et al., 
2021; Shao et al., 2021). 
 
We propose a proof-of-concept open-label clinical trial to evaluate the feasibility and safety of obtaining PET imaging 
scans before and after administration of psilocybin (25mg) with and without risperidone (1 mg) in adults with TRD.  
In this study, 12 participants with TRD will receive 12 hours of manualized psychotherapy that has previously been used 
with psilocybin (Guss et al., 2020). They will also receive either psilocybin 25 mg alone or psilocybin 25 mg plus 
risperidone 1 mg. We are only recruiting patients with TRD, as psilocybin has not demonstrated superiority over first-line 
antidepressants for non-refractory MDD (Carhart-Harris et al., 2021). We are using the atypical antipsychotic risperidone, 

 
 
 
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a potent blocker of the 5-HT2A receptor, because a previous study in healthy volunteers has demonstrated that 
risperidone 1 mg effectively blocks psilocybin’s psychedelic effects (Vollenweider et al., 1998). Although risperidone also 
has actions on dopaminergic receptors, psilocybin has no direct dopaminergic activity (Creese et al., 1975), and 
psilocybin’s psychedelic effects are not blocked by traditional D2-receptor antagonists like haloperidol (Vollenweider et 
al., 1998). In summary, if the proposed proof-of-concept study indicates that psilocybin’s psychedelic effects may not be 
required for its antidepressant effects, and if this is confirmed in a future RCT, the use of psilocybin could be standardized 
and safely expanded without the need for intensive psychotherapy, providing a scalable, novel rapid-acting intervention 
for TRD. 
 
Additionally, this study will include neurophysiological assessments to help to elucidate the biological mechanisms of 
psilocybin for TRD.  Evidence suggests that prefrontal γ-aminobutyric acid (GABA)ergic inhibitory and glutamatergic 
excitatory neurotransmission may represent important neurophysiological targets in therapeutic interventions for TRD 
(Levinson 2010, D Voineskos 2018, 2021) These forms of neurotransmission are effectively indexed via TMS-EEG, with 
the process being refined over the past decade (Tremblay et al Clin Neurophysiol 2019, Chung, Rogasch et al, Brain 
Stimulation 2015).  Evidence of alterations in glutamatergic and GABAergic neurotransmission, measured via TMS-
EEG, has been repeatedly demonstrated after rTMS in TRD populations (Voineskos et al Clinical Neurophysiol 2021, 
Strafella et al, Biological Psychiatry (accepted) 2023). While psilocin, the active metabolite of psilocybin, appears to 
have its main actions on 5HT receptors, it is known that both GABAergic inhibitory interneurons and glutamatergic 
pyramidal neurons, contain multiple 5HT receptors (Smausz et al, Journal of Psychopharmacology 2022). However, the 
direct effects of psilocybin have not yet been elucidated via TMS-EEG. To our knowledge, this would be the first such 
investigation into the potential neurophysiological impact of psilocybin in a TRD population.  
 
An understanding of the mechanisms of psilocybin would facilitate our understanding of the biological models of TRD, 
and the method of action of this novel therapeutic approach.  
 
1.5 
Risks/Benefits 
 
Possible Benefits 
As with any research study, no direct benefit can be promised to research participants. Clinical trials investigating 
psilocybin-assisted psychotherapy in depression cohorts have indicated rapid and dramatic reductions in participants’ 
symptoms. Therefore, participants may receive some benefit from the study if PAP plus risperidone is effective in 
improving depressive symptoms. Participants may also benefit from close monitoring of their clinical conditions.  

 
 
 
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Psilocybin & Risperidone Risks 
Expert consensus indicates that psilocybin is safe in human pre-clinical and clinical trial research (Johnson et al., 2008). 
In addition, in larger RCTs in patients with TRD, risperidone 0.5 – 3.0 mg daily has been safe for use (Cantù et al., 2021). 
Thus, we expect that a single low dose (1 mg) of risperidone to have minimal adverse effects. Risperidone administered 
alone has common side effects (>10%) of drowsiness, headache, tremors, twitching or uncontrollable muscle movements, 
dizziness, nausea, and/or dry mouth. It is possible that participants may experience these side effects but this is unlikely 
with a single 1 mg dose. Previous studies in healthy volunteers indicate that risperidone, a potent blocker of the 5-HT2A 
receptor, can effectively blocks psilocybin’s psychedelic effects (Vollenweider et al., 1998). This study also demonstrated 
that the combination of risperidone 1 mg and psilocybin 25 mg is safe to use in healthy volunteers (Vollenweider et al., 
1998). Psilocybin given at a dose of 25mg is expected to alter mood, cognition, and perception. Common psychological 
and adverse effects of psilocybin include transient anxiety, changes in thought form or thought speed (slowing down or 
speeding up of thought processes), depersonalization, derealization, inattention, impaired concentration, labile mood, 
altered perception of time, altered visual perception, mild paranoid ideas and unusual thoughts. Previous studies indicate 
that these events are transient, tolerable, and largely resolved within the timeframe of the 5-6-hour PAP session (Griffiths 
et al., 2016; Grob et al., 2011; Ross et al., 2016). In addition, these effects are both expected component of the therapeutic 
response and it is anticipated that these effects will be diminished when given with risperidone. Psilocybin can produce 
sympathetic system activation resulting in physiological effects such as pupillary dilation and detectable, but moderate 
increases in blood pressure or heart rate, transient nausea, diarrhea, paresthesia, dizziness, fatigue and headache. In 
rare cases, hallucinogen-induced persistent perceptual disorder (HIPPD) where individuals experience the effects of 
psilocybin for longer than expected. These have not been any reported cases of this in modern clinical settings, but it has 
been rarely reported following recreational use. With proper screening and preparation, psilocybin has a safe physiological 
and psychological profile. As with any investigational product trial, there is a possibility that some participants may 
experience a worsening of their mental state after the drug experience. Reports of this are very rare and have not been 
seen in other similar studies. Published findings on harm profiles associated with drugs most commonly used in the UK 
and Australia consistently rate ‘magic mushrooms’ as being one of the least harmful substances to one’s self and to 
society (Nutt et al., 2010). In order to mitigate risks, a preparatory therapy session will be scheduled with each participant 
to prepare them for what to expect during the experience.  
 
Medication Tapering Risks 
There will be a washout period of a minimum of 2 weeks (4 weeks for fluoxetine) for participants taking any concomitant 
medications. Withdrawing from medications may result in difficulty sleeping, nausea, diarrhea, flu-like symptoms, and 
jitters. These symptoms are not dangerous and usually pass in a few days. In addition, tapering off antidepressant 

 
 
 
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medications can result in the worsening of a participant’s symptoms. During the tapering period, the participant will be 
seen clinically by the study physician. 
 
Blood Draw 
There may be mild temporary discomfort, minor bruising or irritation, and in rare cases there may be local infection at the 
vein site. The blood draws are required to establish safety and eligibility for the trial.   
 
ECG 
Skin irritation from the ECG electrode pads or pain when removing the sticky pads are possible side effects. 
 
TMS-EEG  
Regarding the TMS/EEG visits, the most frequent risk associated with TMS is scalp discomfort, which has been 
reported in approximately 5% of participants. This discomfort is transitory and typically can be resolved with 
acetaminophen. EEG recordings are not associated with any known risks to health and there is no evidence that there 
are either short-term or long-term side effects though some scalp discomfort during the procedure which can occur in a 
small proportion of patients. Single pulse TMS is in routine clinical diagnostic use in hundreds of neurophysiological 
laboratories worldwide. The induced electrical current is well below that which is expected to cause harm to nervous 
tissue. The US FDA has concluded that stimulation at <1 Hz carries virtually no risk of seizure and is therefore classified 
as a non-significant risk device. There is a minimal but slightly increased risk of discomfort, psychological and physical 
harm during these neurophysiological tests. 
 
Assessment Measures 
Assessment measures are designed to address various aspects of psychopathology and as such, may be distressing. 
Participants may experience emotional reactions to the questions and when providing responses about the material on 
the questionnaires and in the interviews. Any distress or discomfort encountered by participants will be addressed by a 
member of the study team. In addition, the assessments may cause fatigue. These risks will be mitigated by offering 
breaks throughout the study visits.  
 
Imaging and Related Risks:  
[18F]SynVesT-1: 
Risks associated with the radiotracer itself are most likely minimal. It is possible, although very unlikely, to have an 
allergic reaction to the radioactive tracer. The amount of radiotracer injected is very small (microgram) and does not 

 
 
 
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usually interfere with the normal functioning of the brain and body based on experience with a large number of research 
studies on many radiotracers. 
Participants will be monitored after injection and throughout the scan. A physician will be available on-site for the 
duration of each scan in case of any issues. 
Radiotracer injection:  
As with any injection or blood work, there is a small risk of bruising or swelling at the site of injection, and 
lightheadedness and feeling faint. Radiotracer injection will be performed by qualified personnel who perform these 
injections routinely. Participants will be monitored after injection and throughout the scan.  
 
Arterial line and blood draw:  
 
There will be a slight discomfort from the insertion of intravenous and arterial lines as well as the possibility of bruising. 
More serious complications are rare but include aneurysm formation (local ballooning of the artery), dissection (rupture 
of the inner artery wall) or local thrombosis (blockage) of the artery, which may require surgical intervention to correct. 
Local anesthesia is used to minimize discomfort during arterial line placement. A qualified professional who routinely 
puts in arterial lines will put in the line. A physician will be available on-site for the duration of each scan in case of any 
issues or discomfort. Participants will be instructed to avoid heavy lifting or sudden wrist movements for 24 hours after 
the arterial line is removed. Participants will be asked if they have donated blood recently and, if so, first PET scan will 
be scheduled at least 30 days after any donation to minimize the impact of multiple blood collection procedures. 
Participants will also be advised not to donate blood for at least 30 days after the second PET scan. 
 
PET scan:  
 
Subjects will be exposed to a small amount of radiation (<0.1 mSv) from a brief transmission or CT scan collected for 
attenuation correction, and will receive ~5 mCi per 18F scan (10 mCi total for the study). The radiation dose is 
comparable to other nuclear medicine scans. The total radiation dose from [18F]SynVesT-1 during the two PET scans 
(including the CT or transmission scans) is about 8.4 mSv. These doses have never been associated with any definite 
adverse effects, but potential long-term risk is unknown. 
Mitigation strategies: A secure central registry at the CAMH PET centre tracks research participants who complete PET 
scans to ensure radiation exposure does not exceed the annual or lifetime limits set by the centre and by the Canadian 
Nuclear Safety Commission. Participants will also be asked about prior PET scans at their screening visit to capture 
nuclear medicine procedures done at other centres or in clinical care. Participants will be asked to void after each PET 
scan to clear radioactive material from the body faster and limit exposure.  

 
 
 
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Reproductive health and pregnancy:  
 
It is advised that pregnant people avoid radiation to minimize any risk to the fetus. Participants will be informed of these 
risks and asked to notify study personnel if they are or become pregnant or are breast-feeding during the study. A urine 
pregnancy test will be administered to all female participants in this study prior to each PET scan, and pregnant women 
will not be scanned. 
 
MRI scan:  
 
Certain metal objects may lead to injuries during the MRI. Some people may feel uncomfortable lying still in the confined 
space of the MRI scanner, tingling sensations are felt by some people during certain scans, or dizziness may be felt for 
a few minutes at the end of the MRI study. Participants will be asked about any metal implants or objects in the body and 
any tattoos. Participants with any metal implants or objects that are not safe for the 3T MRI will not be allowed to enrol or 
continue in the study. Research study staff and the MR technologist will monitor the patient during the scan and pause or 
end the scan in case of anxiety or severe discomfort, or at the participant’s request. 
 
2.0 CLINICAL TRIAL OBJECTIVES  
2.1 
Primary Objective 
To evaluate the feasibility and safety of obtaining PET imaging scans before and after administration of psilocybin (25mg) 
with and without risperidone (1 mg) in adults with TRD. 
 
Hypothesis 1a (feasibility): We will be able to recruit 12 participants within 12 months with a retention of >90%. 
Hypothesis 1b (safety):  Obtaining PET imagining scans before and after administering psilocybin 25mg with and without 
1mg of risperidone will not be associated with serious adverse events. 
 

 
 
 
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2.2 
Exploratory Objectives 
• To obtain preliminary data on synaptic density (as measured by [18F] SynVesT-1 volume distribution, VT) in brain 
regions relevant to MDD (i.e., hippocampus, prefrontal cortex) before and 4 weeks after psilocybin 25 mg vs 
psilocybin 25 mg plus risperidone 1 mg  in adults with TRD. 
• To obtain preliminary data on cortical plasticity, as measured by TMS-EEG and resting EEG in brain regions relevant 
to MDD (i.e., hippocampus, prefrontal cortex) before, during and after psilocybin 25 mg vs psilocybin 25 mg plus 
risperidone 1 mg in adults with TRD. 
 
• To obtain preliminary data on antidepressant effects as measured by the change in the MADRS from Baseline (V2) 
to 1-week post-treatment (V5). Antidepressant effects will also be measured at Weeks 2 (V6), 3 (V7), and 4 (V8) 
post-intervention. Response will be defined as a reduction of 50% or more of the MADRS score and remission defined 
as a score of <7 on the MADRS from Baseline (V1) to Week 1 (V5) 
3.0 CLINICAL TRIAL DESIGN 
3.1 
Overall Design 
 
This study is an open-label, proof of concept study study evaluating the feasibility and safety of obtaining PET imaging 
scans before and after administration of psilocybin (25 mg) with and without risperidone (1 mg) in adults with TRD. The 
preliminary clinical data will help understand the mechanism of antidepressants effects of psilocybin (with and without 
serotonin 2A receptor agonism) in individuals with treatment resistant depression, and inform the development of larger 
mechanistic studies. 
 
Overview of Study Design: 
Participants will be assigned sequentially to one of two open-label groups: (Group 1) 25 mg of psilocybin combined with 
psychotherapy, (Group 2) 25 mg of psilocybin + 1 mg of risperidone combined with psychotherapy. The first six recruited 
participants will be assigned to Group 1 and the second six recruited participants will be assigned to Group 2. Each 
participant will undergo a screening assessment where they will complete lab tests, and clinical and psychiatric 
assessments to determine eligibility. Following the screening visit, participants will undergo a washout period where they 
will be tapered off concomitant medication over a period of 2 to 6 weeks. The length of the tapering period will depend on 
the type of medication the participant is being tapered off (based on the half-life of the medication) and the participant’s 

 
 
 
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preference for the length of the tapering period. Most medications will require a minimum of a 2-week tapering period with 
the exception of fluoxetine which will require a minimum of 4-weeks. Additional time may be added at the discretion of 
the study investigator. During this period, there will be weekly check-ins with the study physician. Participants who are 
not on any prohibited medications will undergo a two-week monitoring period prior to baseline session (Visit 2).  At study 
Visit 2 (Baseline, V2), participants will complete a series of questionnaires and assessments,undergo pre-intervention 
clinical blood work and preparatory therapy with trained study therapists. To reduce participant burden, baseline can be 
broken up into multiple days, however all assessments must be completed within 7-days of the intervention. Ideally, 
baseline occurs the day before the intervention is administered. At study Visit 3 (V3), 12 participants will receive either 25 
mg of psilocybin in conjunction with supportive therapy (Group 1: first six recruited participants) or 1mg of risperidone and 
60-minutes later will receive an active dose (25mg) of psilocybin in conjunction with supportive therapy. On the day after 
the dosing session (Visit 4, V4) and one-week after the dosing session (Visit 5, V5), participants will be asked to complete 
the same questionnaires that were done at Baseline (V2) and will undergo an integrative therapy session with the trained 
study therapists. At Visit 4, participants will undergo post-intervention clinical bloodwork. At Visit 6 (V6), Visit 7 (V7), and 
Visit 8 (V8), participants will complete follow-up assessments similar to those administered at Baseline (V2). 
 
Additionally, participants will undergo neurophysiolpogical testing (TMS-EEG) at baseline (visit 2), intervention (visit 3) 1-
2 hours after receiving the intervention and at the end of the intervention day), and at follow-up (visit 5). 
 
Participants will also undergo three scans: (1) A pre-treatment [18F]SynVesT-1 PET scan (up to 4 hours), (2) An MRI scan 
used for co-registration of PET images (up to 1 hour) and (3) a post-treatment   [18F]SynVesT-1 PET scan (up to 4 hours).  
 
Pre-treatment imaging scan will be collected before the study treatment visit. Post-treatment scan will take place between 
1 and 6 weeks after treatment. All study procedures are expected to be completed within 3 months of enrolment, depending 
on scheduling of the trial treatment visit. 
 
Positron emission tomography 
PET scans will be acquired with a GE Discovery MI 5-ring PET/CT scanner or with a high-resolution research tomograph 
(HRRT). Before each emission scan, following the acquisition of a scout view for accurate positioning of the participant, 
a low dose (about 0.1 mSv) CT scan (for the PET/CT scanner) or transmission scan (for the HRRT) will be acquired and 
used for attenuation correction. Otherwise, procedures will be identical for both scanners. Custom-made thermoplastic 
facemasks (Orfit, Antwerp, Belgium) together with a head-fixation system will minimize head movement in the PET 
scanner. Up to 5 mCi (+/- 10%) of the radioactive tracer will be injected as a bolus into an intravenous line placed in the 
antecubital vein. Participants will undergo up to 125-minute acquisition scan. 

 
 
 
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PET scans will use an arterial line to obtain samples of arterial blood (up to 160 mL) throughout the scan, which are used 
in conjunction with the PET scan measure in the brain to calculate and validate the binding measure. Prior to insertion, 
lidocaine, a local anesthetic is applied in a small dose to numb the area and to make the insertion of the catheter easier. 
The arterial line is inserted by a registered respiratory therapist with a long-standing expertise in arterial line insertion, as 
is customary at our Centre. Arterial blood will be drawn automatically from a radial artery using an automated blood 
sampling system (ABSS) pump throughout the scan (total automatic volume, approx. 81 mL) and manually at discrete 
time points (-5, 2.5, 7, 12, 15, 20, 30, 45, 60, 90, and 110 minutes, where t=0 is scan start time; total manual volume, 
approx. 61 mL). The removal of the arterial line will be done by a qualified health care professional. The procedure will 
include the application of pressure at the site of arterial line insertion for about 25 minutes and/or until the puncture site 
has stopped bleeding (whatever happens first). After that, an elastic bandage will be applied to the wrist where the line 
was inserted. Participants will be instructed to avoid activities that involve sudden wrist movements or lifting heavy items 
with this hand for 24 hrs. 
 
In the event that an arterial line cannot be placed or fails before scan start, the scan may proceed without an arterial line 
at the discretion of the investigators and alternate analysis methods will be used (i.e., reference region quantification 
using the simplified reference tissue 2 (SRTM2) model, which provides a comparable measure of synaptic density using 
only brain data – see Data Analysis). In the event of radiochemistry failure or equipment malfunction, the PET scan will 
be rescheduled if the participant agrees and if schedules allow. 
 
Magnetic resonance imaging:  
MRI imaging will take place at the CAMH Brain Health Imaging Centre. The MRI will take approximately 1 hour including 
scanner set-up. 
 
A 3 T GE Discovery MR750 MRI system (General Electric, Milwaukee, WI) will be used to acquire whole-brain scans for 
spatial normalization of parametric PET images (anatomical T1-weighted and proton density-weighted MRI scan). If 
time allows within the one-hour imaging session (including setup), scans measuring brain activity at rest will also be 
acquired (resting state functional MRI scan, approximately 15 minutes). Throughout anatomical and functional imaging 
scans, participants will rest comfortably on the scanner bed in a dimly lit room monitored by MR technicians. 
 
Neurophysiology: 
TMS will be administered over the frontal cortex,  with simultaneous EEG recording. Cortical inhibition will be assessed 
via the Short Intracortical Inhibition (SICI) paradigm.  SICI is a paired-pulse paradigm that can be used to index inhibitory 

 
 
 
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of the cortex, whereby a conditioning stimulus (CS) at 80% of RMT is presented at 2ms before a test stimulus (TS) at 
120%RMT. SICI is mediated by fast-acting ionotropic GABAA receptors [Ilic et al 2002]. This suggests that SICI arises 
when the conditioning stimulus (CS) activates a low-threshold inhibitory system, leading to hyperpolarizing inhibitory 
postsynaptic potentials (IPSPs) that suppress the cortical output evoked by the subsequent test stimulus (TS). Each 
testing session will involve the administration of up to 500 TMS pulses using a randomized sequence of single (TS) and 
paired (SICI) paradigms. 
Biphasic TMS pulses will be administered using a Magventure B65 coil. Each TMS session will include the establishment 
of the individual threshold for the resting motor threshold (RMT). The RMT will be determined according to the protocol 
outlined by Rossini et al. The coil is held tangentially to the head, with the handle of the coil pointing backward and 45 
degrees laterally from the midline. The RMT is defined as the minimum stimulus intensity that elicits an MEP of more than 
50 mV in five of ten trials. 
 
In addition, before the TMS-EEG paradigms, we will collect 5 minutes each of resting-state, eyes-closed and eyes-open 
EEG. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
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Figure 1. Study Schematic:  
 
 
 
 
Timeline 
In total, there are a minimum of 12 study visits (8 study visits, 2 imaging visits and a minimum of 2 check-in visits during 
the washout period). There may be more study visits scheduled at the discretion of the study team or the participant. 
These study visits will take place over the span of approximately 2.5 months. The total expected duration of the clinical 
trial from the time the study team starts recruiting until data analysis has been complete is 18-months. Following a 3-
month startup period, the study team will recruit approximately 1 participant per month over the period of 12 months. 
Study interventions and follow-up assessments will be completed by month 14. This leaves approximately 4 months for 
data analysis which will be completed at month 18.  
 
 

 
 
 
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3.2 
Primary Endpoints 
Safety endpoints will be evaluated using standardized adverse events monitoring at all 
time points. Adverse event monitoring will be prioritized to closely and thoroughly evaluate 
the acute and sub-acute psychological safety profile. Constant observation by therapists 
will monitor for adverse events during the dosing sessions. An on-call psychiatrist will be 
available at all times to further assess as needed for acute concerns. The safety endpoint 
is the number and severity of adverse events reported throughout the duration of the trial.  
 
 
Feasibility endpoints include the recruitment and retention rates. Dropout rates during 
three periods will be evaluated, namely: 1) screening period in which the participant 
undergoes medication tapering and washout; 2) during the acute course of the study 
intervention; and 3) during the follow-up after the intervention. Throughout all three 
periods, we will also evaluate adverse events including psychological distress and serious 
adverse events (e.g., hospitalization, suicide attempt, death).  
 
 
 
4.0 PARTICIPANT SELECTION AND WITHDRAWAL 
4.1 
Target Population 
The target population for this study are adults aged 18-65 who are diagnosed with major 
depressive disorder and experiencing a clinically significant depressive episode that has 
failed to respond to at least two adequate trials of antidepressants. Participants must meet 
all inclusionary/exclusionary study criteria as confirmed by the study investigator. In order 
to be eligible, these criteria must be met at the Baseline visit (V2). For participants on 
concomitant medications, confirmation of eligibility occurs after a successful washout 
period in which the participant has been tapered off concomitant medications for a period 
of at least 2-weeks prior to baseline (4-weeks for fluoxetine), as confirmed by the study 
investigator.  
4.2 
Participant Recruitment and Screening 
The target sample size is 12 participants (N=12) diagnosed with treatment-resistant 
depression. The study will take place at a single site: the Centre for Addiction and Mental 
Health (CAMH) in Toronto, Ontario.  
 
The source of participants in this study will come from CAMH outpatient units and external 
healthcare providers. Clinicians at CAMH may identify potential research participants and 
obtain verbal permission from these potential participants for a member of the research 
team to approach them. Potential participants that are interested in participating in the 
study will be prescreened by a member of the study team, as outlined below. 
 

 
 
 
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The CAMH Research Registry will also be used to recruit participants for this clinical trial.  
Upon REB approval to use the Research Registry as a recruitment strategy, authorized 
research personnel will search and contact potential research participants included within 
the member database of the Research Registry for study participation. This clinical trial 
will also be posted on the Research Registry website, as well as the public CAMH 
website. The recruitment material posted on these websites will be reviewed and 
approved by Research Communications as well as the REB prior to posting. Once posted, 
interested participants can use the “Find a CAMH study” feature to explore clinical trials 
that they are interested in.  
 
Prescreening Procedures 
Once a potential participant contacts the research team or is referred to the research 
team as an interested potential participant, a research team member will schedule a 
phone call. This phone call will be referred to hereafter as the Pre-Screening 
conversation. During the pre-screening conversation, a brief description of the study is 
provided to the potential participant and then, if the person agrees, the following eligibility 
criteria is obtained: 
• Contact information (phone number and/or email) 
• Partial date of birth  
• Ability to read and speak English 
• Whether they have a clinical diagnosis of major depressive disorder 
• Whether they are currently experiencing a major depressive episode 
• Treatments taken for major depressive episode (frequency and type of treatment) 
• Whether the potential participant has been diagnosed with psychotic disorder, 
bipolar disorder, paranoid personality disorder, schizoaffective disorder, or 
borderline personality disorder; 
• Diagnosis of a substance use disorder (excluding tobacco) within the previous 6-
months; 
• If they are currently undergoing therapy and if they are, the date that they started 
• Whether the potential participant would be willing to discontinue current 
antidepressant medications  
• Whether they are seeing a doctor on a regular basis for a medical problem 
• If they are currently taking medications for the treatment of a physical health 
problem 
• Difficulty with giving blood or needles 
• Currently nursing or pregnant 
• Willingness to take contraceptives for the duration of the study starting atleast one 
month prior to screening visit (Visit 1) 
• History of allergy or adverse reaction to risperidone 
• Currently enrolled in another study involving an investigational product or device 
• If they are able to take medication orally 
• History of traumatic brain injury, neurological or neurodegenerative disorder 
• Willingness to participate in PET and MRI scans 
• History of claustrophobia 

 
 
 
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• History of pacemaker implantation 
• Blood disorders, disorders of coagulation, or ongoing use of anticoagulant 
medication 
• Any disability that may prevent the participant from completing study 
requirements (e.g., non-correctable clinically significant sensory impairment such 
as not hearing well enough to communicate with study personnel during scans, 
or physical disability that does not allow them to lie still on the scanner bed for 1-
2 hours 
• A history of metal implants in the body 
 
The information collected during this conversation will be recorded on the pre-screen form 
which will be reviewed by the study PI. If the potential participant does not meet any 
exclusionary criteria as listed on the Pre-Screen form, then the potential participant is 
called back to invite them to schedule a consent and screening visit.  
 
If the person meets any exclusionary criteria during the pre-screening conversation or as 
determined by the study investigator, then the person is asked whether they would be 
interested in participating in any other studies (current or future) within our program. If 
they are interested in other studies within our department, their name and contact 
information will be transferred to a password protected log that is only accessible by 
Centre for Complex Interventions staff. If they fail the pre-screen and do not wish to be 
contacted, their pre-screen form will be discarded in the confidential shredding bin which 
will then be securely disposed of. However, their name will be kept in a password 
protected log along with the date and result (pass/fail) of their pre-screen so if they contact 
us again (e.g. to inquire about their eligibility) we can refer back to it.  
 
 
Compensation 
Participants will not be charged for research-only services for their participation in this 
study. All research-only services, such as clinical assessments, blood work, and the IP 
will be provided at no cost to the participant.  
 
Participants will be reimbursed for the cost of parking incurred at each study visit. To 
receive reimbursement for parking expenses incurred at each study visit, participants 
must provide the research team with a parking receipt. In addition, reimbursement will be 
provided if the participant used public transit for transportation to and/or from study 
appointments.  
 
Participants will also be reimbursed for the time spent at study visits occurring after the 
screening and washout period where treatment (therapy or the intervention) is not 
administered. Participants will be reimbursed $10 per hour for each study visit that they 
attend (V6, V7, and V8). Participants will also be compensated for their scans: 150.00 for 

 
 
 
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each PET scan and 60.00 for the MRI scan. In total, if participants complete all study 
visits, they may be reimbursed up to $385 for their time.  
Compensation will be provided at the end of the sessions via  e-gift card, if the session is 
conducted virtually. No payment will be provided in advance.  
 
Study Visit: 
Duration: 
Compensation: 
PET scan 1: [18F]SynVesT-1 scan with arterial line 
~4 hours 
$ 150 
PET scan 2: [18F]SynVesT-1 scan with arterial line 
~4 hours 
$ 150 
MRI scan 
~1 hour 
$ 60 
Follow-Up: Visit 6 
~1 hour 
$10 
Follow-Up: Visit 7 
~ 30 min 
$5 
Follow-Up: Visit 8 
~1 hour 
$10 
 
 
4.3 
Equity, Diversity and Inclusion Considerations 
Equity, diversity, and inclusion (EDI) are important to ensuring the study design is ethically 
sound. No exclusions will be made based on race, ethnicity, religion, sex, or gender.  
 
4.4 
Eligibility Criteria 
4.4.1 
Inclusion Criteria 
The participant must meet all of the inclusion criteria to eligible for this clinical trial: 
 
1. Adults 18 to 65 years old; 
2. Must be deemed to have capacity to provide informed consent; 
3. Must sign and date the informed consent form; 
4. Stated willingness to comply with all study procedures; 
5. Ability to read and communicate in English, such that their literacy and comprehension 
is sufficient for understanding the consent form and study questionnaires, as 
evaluated by study staff obtaining consent; 
6. Primary DSM-5 diagnosis of non-psychotic MDD, single or recurrent, based on the 
Structured Clinical Interview for DSM-5 (SCID-5) administered at the first screening 
visit; 
7. Participants diagnosed with treatment-resistant depression defined as individuals with 
a baseline HamD-17 score > 14 and that have not responded to two or more separate 
trials of antidepressants at an adequate dosage and duration (an antidepressant 
resistance rating score of three or more is considered an adequate trial)  based on the 
Antidepressant Treatment History Form (ATHF); there is no upper limit on the number 
of treatment failures; 
8. Ability to take oral medication; 

 
 
 
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9. Individuals who are capable of becoming pregnant: use of highly effective 
contraception for at least 1 month prior to screening and agreement to use such a 
method during study participation; 
10. Individuals who are willing to and have tapered off current antidepressant and 
antipsychotic medications for a minimum of 2-weeks (or more depending on the 
medication) prior to Baseline (V2) and whose physician confirms that it is safe for them 
to do so;  
11. Agreement to adhere to Lifestyle Considerations (section 4.5) throughout study 
duration. 
4.4.2 
Exclusion Criteria 
An individual who meets any of the following criteria will be excluded from participation in 
this clinical trial: 
1. Pregnant as assessed by a urine pregnancy test at Screening (V1) and Baseline (V2) 
or individual’s that intend to become pregnant during the study or are breastfeeding; 
2. Treatment with another investigational drug or other intervention within 30 days of 
Screening (V1); 
3. Have initiated psychotherapy in the preceding 12 weeks prior to Screening (V1); 
4. Have a DSM-5 diagnosis of substance use disorder (use of tobacco is permitted) 
within the preceding 6 months; 
5. Have active suicidal ideation with intent and plan as determined by item 3 of the 
HamD-17; 
6. Any DSM-5 lifetime diagnosis of a schizophrenia-spectrum disorder; obsessive-
compulsive disorder, psychotic disorder (unless substance induced or due to a 
medical condition), bipolar I or II disorder, paranoid personality disorder, borderline 
personality disorder, or neurocognitive disorder as determined by medical history and 
the SCID-5 clinical interview; 
7. Any first-degree relative with a diagnosis of schizophrenia-spectrum disorder; 
psychotic disorder (unless substance-induced or due to a medical condition); or 
bipolar I or II disorder as determined by the family medical history form and 
discussions with the participant; 
8. Presence of a relative or absolute contraindication to psilocybin, including a drug 
allergy, recent stroke history, uncontrolled hypertension, low or labile blood pressure, 
recent myocardial infarction, cardiac arrhythmic, severe coronary artery disease, or 
moderate to severe renal or hepatic impairment. 
9. Presence of baseline prolonged QTc or Torsade de Pointes as measured by the ECG 
or a history of long QTc syndrome or related risk factors; 
10. History of allergy or contraindication to risperidone  
11. Current or past traumatic brain injury or other neurological/neurodegenerative 
disorder 
12. Unable or unwilling to undergo PET or MRI scanning (e.g. claustrophobia, 
pacemaker); 
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14. Any disability that may prevent the participant from completing study requirements 
(e.g., non-correctable clinically significant sensory impairment such as not hearing 
well enough to communicate with study personnel during scans, or physical disability 
that does not allow them to lie still on the scanner bed for 1-2 hours); 
15. Participant exceeds the annual or lifetime amount of radiation 
16. Any other clinically significant physical illness including chronic infectious diseases or 
any other major concurrent illness that, in the opinion of the investigator, may interfere 
with the interpretation of the study results or constitute a health risk for the participant 
if they take part in the study.  
4.5 
Lifestyle Considerations 
During this clinical trial, participants are asked to: 
• Abstain from alcohol for 24 hours before baseline and for up to 6hrs after intervention 
administration (V3). 
• Abstain from the use of any prescribed opioids, benzodiazepines, or sleep aids (Z-
drugs) within 12hrs prior to the intervention (V3) and for up to 6hrs after administration.  
• Abstain from any illicit drugs (e.g. cocaine, ecstasy/MDMA, hallucinogens) and/or 
cannabis for the duration of the study. Presence of these substances will be assessed 
at a urine drug screening at Visit 1 and Baseline (V2) 
• Abstain from driving or operating heavy machinery for up to 24hrs after the intervention. 
4.6 
Screen Failures  
Screen failures are defined as participants who consent to participate in the clinical trial 
but do not meet one or more eligibility criteria required for participation. The screening 
period for participants in this study occurs before Baseline (V2) and eligibility for the study 
cannot be confirmed until the participant has tapered off any concomitant medication. In 
order to be eligible, the participant must meet all eligibility criteria as outlined in Section 
4.4. The information collected about the participant during the screening process 
including demography, screen failure details, eligibility criteria not met, and any AEs/SAEs 
will be used for the purposes of transparent reporting. Participants who are deemed 
ineligible will continue with their usual standard of care or may be referred to other 
research protocols for TRD.  
 
4.7 
Participant Withdrawal Criteria 
4.7.1 
When and How to Withdraw Participants 
 
Participants are free to withdraw from participation in the clinical trial at any time.  
An investigator will discontinue or withdraw a participant from the clinical trial for the 
following reasons: 
• Pregnancy or if participants cease effective contraception; 
• Significant study intervention non-compliance; 

 
 
 
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• If any adverse event (AE), laboratory abnormality, or other medical condition or 
situation occurs such that continued participation in the clinical trial would not be in the 
best interest of the participant; 
• Disease progression which requires discontinuation of the study intervention; 
• If the participant meets an exclusion criterion (either newly developed or not previously 
recognized) that precludes further study participation; or 
• If the participant develops or is found to have any condition that may confound 
interpretation of the primary PET outcome measure, the participant will be withdrawn 
from the study. 
• Participants developing severe claustrophobia during imaging (MRI or PET) will be 
withdrawn to prevent any risk of severe anxiety to the participant 
 
 
The reason for participant discontinuation or withdrawal from the study will be recorded      
within the participant’s research record, and/or health record at CAMH. 
 
Participants that are withdrawn from the study will be replaced using the same recruitment 
methods as outlined in Section 4.2: Participant Recruitment and Screening.  
 
4.7.2 
Follow-up for Withdrawn Participants 
 
If a participant withdraws consent, the information that was provided by the participant 
and recorded by the study team before they withdrew consent will not be destroyed. 
However, once withdrawn from the clinical trial, no further research procedures or 
evaluations will be performed, or additional research-specific data collected on the 
participant. Reasonable effort will be made to obtain permission to document the reason 
for withdrawal.  
 
Withdrawn participants will be seen clinically by the study investigator to ensure a plan 
for continued care outside of the study is established. If the participant is interested in 
hearing about other treatment options, they may be offered a referral to the CBT group at 
CAMH and/or a consultation with a psychiatrist to discuss pharmacotherapy options.   
4.7.3 
Early Termination Visit 
If a participant withdraws from the clinical trial, every effort should be made to perform an 
Early Termination Visit. 
 
Participants that withdraw after the first dosing session:  
If the participant is willing to attend an early termination visit, the following information will 
be documented: 
• Assessment of new and ongoing AEs; 
• Assessment of any complications following the study intervention; 
• Documentation of all concomitant medications; 

 
 
 
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The PI will also ensure the participant is appropriately transitioned/followed for any 
additional care as required. 
 
 
4.7.4 
Participants who are Lost to Follow-up 
A participant will be considered lost to follow-up if they fail to return for 2 or more 
scheduled visits and is unable to be contacted by the research team.  
 
The following actions will be taken if a participant fails to attend a required study visit: 
• The research team will attempt to contact the participant and reschedule the missed 
visit 7 days, counsel the participant on the importance of maintaining the assigned visit 
schedule, and reconfirm whether the participant wishes to and/or should continue in 
the clinical trial.  
• Before a participant is deemed lost to follow-up, the research team will make every 
effort to regain contact with the participant via 2 different methods of contact (e.g. 
telephone and email). These contact attempts should be documented in the 
participant’s research record and/or legal health record.   
• Should the participant continue to be unreachable, they will be considered to have 
withdrawn from the clinical trial with a primary reason of lost to follow-up. 
 
5.0 STUDY INTERVENTION  
5.1 
Description 
 
Pharmacokinetics and Psilocybin Effects 
Psilocybin is detectable in plasma 20 to 40 minutes after oral administration of 0.224 
mg/kg (10-20mg total dose) (Hasler et al., 1997). Orally ingested psilocybin is 
metabolized in the liver, and primarily transformed into the active hydroxyl metabolite, 
psilocin. Psilocybin is essentially a prodrug and psilocin represents the pharmacologically 
active agent in systemic circulation. The elimination half-life of psilocybin is 50 minutes 
(Lindenblatt et al., 1998). Psilocin’s half-life ranges between 2 and 3 hours and it 
detectable 6 hours after oral administration (Hasler et al., 1997; Hasler et al., 2004; 
Lindenblatt et al., 1998). Both psilocin and psilocybin are detectable in human urine, 
unmodified and particularly conjugated with glucuronic acid(Hasler et al., 2002). The 
majority of psilocybin recovered in urine is excreted within 3 hours after oral administration 
and is completely eliminated from the body within 24 hours (Hasler et al., 2002).  
 
As a 5HT2A/2C agonist, psilocin is regarded as a “classical” psychedelic; in humans, it 
commonly elicits significantly altered states of consciousness, experienced through 
visual and sometimes auditory effects, changes in perception, distortions of time, and a 
range of effects including a sense of awe, novel perspectives, existential and personal 
insight, dramatically heightened empathy and feelings of compassion, strong emotions, 
and non-dual or unitive experience. A number of these ‘peak’ experiences have been 

 
 
 
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associated with improved quality of life and improvement in mood (Griffiths et al., 2016; 
McClain et al., 2003; Visser et al., 2010). For a more detailed explanation on the effects 
of psilocybin and its mechanism of action, please refer to the investigators brochure.  
 
Pharmacokinetics and Risperidone Effects 
Risperidone is an atypical antipsychotic with antagonist binding affinity at 
serotoninergic, dopaminergic, adrenergic, and histaminergic receptors (Schatzberg & 
Nemeroff, 2009). It has a very high affinity for the 5-HT2A receptor (Meltzer et al., 1989) 
and moderately high affinity for the D2 dopamine receptor (Schatzberg & Nemeroff, 
2009).  Risperidone is taken orally and almost entirely absorbed in the GI tract and 
metabolized in the liver (Schatzberg & Nemeroff, 2009). The plasma half-life is 
approximately 3 hours in extensive metabolizers and 20 hours in poor metabolizers 
(Broder et al., 2012). Clearance values for risperidone and the active metabolite are 
estimated to be 4.6 and 6L/hr, respectively (Vandenberghe et al., 2015). In general, 
risperidone is well-tolerated. It does have a broad range of common side effects (>10%) 
which include somnolence, nausea, dizziness, dry mouth, and tremor (Chopko & 
Lindsley, 2018). Risperidone has been shown to improve depression in SSRI-resistant 
patients (Correia & Vicente, 2007). In healthy subjects, risperidone (1 mg) blocked (98-
99%) the psychedelic effects of psilocybin including the perceptual disturbances and 
hallucinatory phenomena (Vollenweider et al., 1998). 
 
Psilocybin-Assisted Psychotherapy 
The participant will attend 1 preparatory session that occurs within 7-days of the first 
psilocybin dosing session (V3) to develop a therapeutic alliance, set intentions for the 
experience, and learn what to expect during the dosing session. An additional 
preparatory therapy session can be added at the discretion of the study therapists and 
study investigator. In addition, the participant will undergo 2 integrative therapy sessions 
after the intervention (V4 & V5). During dosing, there will be two therapists present. A 
physician will be available at all times during the dosage session to assess and manage 
any medical or psychiatric adverse events (either on-call or as a therapist in the room 
with the patient). Efforts will be made to ensure that the therapists remain the same at 
every therapy session, however the only day that requires two therapists is dosing. 
Therapy sessions will not be video recorded.  
Each  therapist will undergo training using the Yale Manual for Psilocybin-Assisted 
Therapy of Depression, an evidence informed protocol for PAP. For a full description of 
each therapy session and PAP, please refer to the Yale Manual for Psilocybin-Assisted 
Therapy of Depression. For a full description of each therapy session and PAP, please 
refer to the Yale Manual for Psilocybin-Assisted Therapy of Depression. Therapy 
sessions will not be video recorded. At least one of the therapists will be a clinician and 
will be available at all times during the dosage session to assess and manage any 
medical or psychiatric adverse events. 

 
 
 
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In addition, therapists will undergo protocol-specific training for the study. Therapists 
involved in the trial must be licensed to provide therapy by a regulatory body. 
Unlicensed therapists will be directly supervised by a licensed therapist.  
Requirements for lead study therapists: 
Licensed to provide psychotherapy in the province of Ontario:  
Social worker 
Psychologist 
Psychiatrist or physician (M.D or equivalent) with psychotherapy training 
Nurse with psychotherapy training (e.g. nurse psychotherapist certificate) 
Registered with the appropriate regulatory body in Ontario: 
College of Registered Psychotherapists of Ontario 
College of Psychologists of Ontario 
Ontario College of Social Workers and Social Service Workers 
The College of Physicians and Surgeons of Ontario 
College of Nurses of Ontario 
Previous experience administering PAP 
Unlicensed therapists who are in the process of becoming licensed or therapists who 
have not had any PAP experience must be supervised under the direct supervision of a 
lead therapist.   
 
How the study intervention will appear: 
The psilocybin will be provided by Filament Health Corp. (Burnaby, British Columbia, 
Canada). The dose of psilocybin used in this study will be 25mg. The psilocybin will be 
administered in size 2 hydroxypropyl methyl cellulose (HPMC), white capsules. The 
risperidone (where applicable) will be provided by CAMH pharmacy and will appear as a 
1mg oral tablet. 
5.2 
Treatment Regimen 
There will be one intervention day (V3 – Day 0) following Baseline (V2) and after the 
participant has been deemed eligible to participate. The procedures are outlined below: 
 
Each participant will be assigned 1 treatment bottle containing 1 capsule of 25mg 
psilocybin and, where applicable, 1 treatment bottle containing 1 tablet of 1mg of 
risperidone. For participants allocated to Group 2, under the supervision of a clinician, the 
1mg tablet of risperidone will be taken orally and the 25 mg capsule of psilocybin will be 
taken 60 minutes after with a glass of water. For participants in Group 1, under the 
supervision of a clinician, the 25 mg capsule will be taken orally with a glass of water. 
There will be no modifications to the dosage, each participant will receive the same 

 
 
 
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dosage of psilocybin. All participants in Group 2 will receive the same dose of risperidone.  
However, if adverse effects are experienced, the study clinician may make changes to 
the intervention, which include therapy after each session. The study clinician may decide 
that participants may require more therapy sessions. In addition to the psilocybin, two 
study therapists trained in psilocybin-assisted psychotherapy will be supporting the 
participant during the dosing session. There will be 1 therapist present at all times 
throughout the dosing session. The total treatment time will be 5-6 hours when the acute 
effects of the psilocybin have passed. 
 
5.3 
Method for Assigning Participants to Treatment Groups 
The first six recruited participants will be assigned to the Group 1: 25 mg of psilocybin 
combined with adjunct supportive therapy. The second six recruited participants will 
be assigned to Group 2: 25 mg of psilocybin plus 1 mg of Risperidone combined with 
supportive therapy.  
5.4 
Administration of Study Intervention 
 
The IPs will be prepared by the CAMH pharmacy and picked up by a trained research 
staff member. The IPs will be given to the participant by the study clinician who will 
supervise the participant orally take the medication. Participants in Group 1 will receive a 
capsule containing 25mg of psilocybin which will be taken orally, with water. Participants 
in Group 2 will receive a tablet of 1mg of risperidone taken orally followed 60-minutes 
later by a capsule containing 25mg of psilocybin which will also be taken orally, with water. 
The remaining 10 participants will receive one 25mg tablet of psilocybin, which will be 
taken orally with water. The capsules should not be opened or chewed. 
  
After taking the IPs, the participant will lie down on a bed in a non-clinical environment. 
Therapists will encourage participants to focus their attention inward and stay with any 
experience that arises. To enhance inward reflect, a pre-selected music playlist will be 
played quietly. Two study therapists trained in PAP will be supporting each participant 
during the dosing session with at least one therapist being present at all times to respond 
to the emotional and physical needs of the participant. Constant observation by therapists 
will monitor for adverse events during the dosing sessions. At least one member of the 
dyad will be a clinician. An on-call psychiatrist will be available at all times to further 
assess as needed for acute concerns. 
 
Where applicable, the effects of risperidone will take approximately 60 minutes after 
administration. The effects of psilocybin usually start about 20 to 30 minutes after 
administration, becoming the most intense in the first 90 to 120 minutes and gradually 
subsiding in 5 to 6 hours. The participants will be asked to remain in the room for the 
duration of the session regardless of the intensity of the effects, preferably lying down 
and mostly silent unless they have a concern or need to communicate a discomfort or 
seek reassurance from the therapist, or use the restroom. The therapists will ‘check-in’ 
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dosing. Light snacks will be available, though participants are encouraged to bring their 
own lunch.  At approximately 1-2 hours after receiving the intervention, participants will 
undergo neurophysiological testing 
 
 
About 5 to 6 hours after dosing, the trained therapists will discuss the IP administration 
experience with the participant. Additional neurophysiological testing will take place at the 
end of the intervention day prior to participant dishcharge.  The participant will be 
discharged 5-6 hours post-dosing when, in the opinion of the investigator, the acute 
effects of psilocybin are resolved. The participant must be accompanied home by a 
caregiver who will remain with the participant for up to 24hrs after the intervention was 
given. The study team is to be notified that the participant has arrived home safely via 
phone call. In the absence of receiving a phone call, the study staff will directly contact 
the participant.  
 
5.5 
Participant Compliance Monitoring 
The IP will be administered to the participant in front of study personnel. Thus, 
administration of the IP will be supervised by study personnel to ensure compliance.  
5.6 
Concomitant Therapy 
All prescription and non-prescription medications (e.g. over-the-counter drugs and herbal 
supplements) that participants report taking during the 30 days prior to Screening (V1) 
will be assessed and recorded at V1. For each medication, documentation should list the 
trade or generic name, the total daily dose including units (or the dose, units, and 
scheduled and actual frequency of administration if the medication is not taken daily), the 
route of administration, and the reason for use. Where applicable, medication reports 
should be corroborated with participant medical records. All as-needed (pro re nata, PRN) 
prescriptions should be converted to reflect the actual number of pills or dose taken per 
day. 
 
Concomitant medication refers to all drugs and therapies used from the time the ICF is 
signed through until the end of study participation. 
Changes, additions, 
or 
discontinuations to medications and/or therapy will be assessed, recorded, and verified 
with participants in the data collection forms during each study visit.  
 
Permissible Medications 
Medications for the management of concurrent anxiety and insomnia, or non-psychiatric 
medications that have a potential psychotropic effect are permitted within the following 
limitations. 
 
For the initial Screening Visit (V1) through to the final study visit (V8), participants are 
permitted to use benzodiazepines (up to 2mg of lorazepam equivalent per day for 
insomnia and anxiety if it is not taken within 12 hours before the psilocybin dose. 
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as needed for non-psychiatric conditions (e.g. pseudoephedrine for allergies or cold, 
zoplicone for sleep disorders) should be used no more than 2 times a week and not within 
12 hours before any study assessment. Documentation of the use of adjunctive 
anxiolytics, hypnotics, or medication with potential psychotropic properties (including 
over-the-counter preparations) will be obtained at each visit.  
 
Permissible Contraceptive Methods 
A woman/female or person who is not of childbearing potential is considered to be 
postmenopausal after at least 12 months without menstruation. The participant must be 
on a permissible contraceptive for a minimum of 1 month prior to screening and for the 
duration of the study. The following methods of contraception, if used properly and used 
for the duration of the study, are permissible: 
 
• Combine 
estrogen-and 
progestogen-containing 
hormonal 
contraception 
associated with inhibition of ovulation: 
o Oral 
o Intravaginal 
o Transdermal 
• Progestogen-only hormonal contraception associated with inhibition of ovulation: 
o Oral 
o Injectable 
o Implantable 
• Intrauterine device 
• Intrauterine hormone-releasing system 
• Bilateral tubual occlusion 
• Vasectomized partner 
• Sexual abstinence 
• Tubal ligation/ occlusion 
 
Periodic abstinence (e.g. calendar, symptothermal, or postovulation methods) is not an 
acceptable form of contraception for this study. 
 
These methods of contraception also apply to partners of male participants.  
 
The investigator (or delegate) and each participant will determine the appropriate method 
of contraception for the participant during the participation in the study. This will be 
documented at Screening (V1). 
 
 
Prohibited Medications 
Participants are to be discontinued from antidepressants and/or antipsychotic 
medications at least 2 weeks prior to Baseline (V2). Participants on fluoxetine will be 
taped off the medication at least 4-weeks prior to Baseline (V2). Additional time may be 
required as determined by the study investigator. Medications that must be discontinued 
include the following 2 classes of the Anatomical Therapeutic Chemical (ATC) 

 
 
 
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Classification System: NO5A Antipsychotics & NO6A Antidepressants. Methylphenidate 
is also included in this list. In addition, participants must also taper off inhibitors of 5'-
diphospho-glucuronosyltransferase (UGT)1A9 and 1A10, aldehyde dehydrogenase 
inhibitors (ALDHs), and alcohol dehydrogenase inhibitors (ADHs)  for a minimum of 2-
weeks (or more depending on the medication) prior to Baseline (V2). 
 
These medications should not be re-introduced until after Week 4 (V8) when the study is 
complete. If the medications are re-introduced, the study investigator must be notified and 
the medications will be documented in the data collection form. Participants who require 
concomitant medication(s) specifically for the treatment of depression at any time through 
the duration of the study will be assessed for reasons of resuming their medications. 
 
 
Rescue Medication 
The decision to medicate a participant will depend on if the therapists and study 
investigator determine the safety of the patient and others can be maintained without 
medical intervention. The final decision will be made by the study investigator. 
• Benzodiazepine anxiolytics 
o The preferred pharmacological intervention of choice in case of acute 
psychological distress (e.g. medications such as lorazepam or alprazolam 
that have a rapid onset, a short time until peak plasma concentration, and 
a short duration of therapeutic action).  
o The oral route is preferable because IV injection procedures may further 
exacerbate the participant’s anxiety. 
• Antipsychotic medications (e.g. additional risperidone) should be available in the 
event that an adverse reaction escalates to unmanageable psychosis.  
• Management of blood pressure: 
o Asymptomatic with blood pressure (BP) < 180/100 
 Reassure, ensure lights are dim or off, tilt head of bed 15 degrees 
up and continue to monitor 
 Increase blood pressure measurement frequency to q15min until 
BP has partly normalized (sBP = 100-159; dBP = 60-99)  
o Asymptomatic with BP >180/100 for >30 minutes 
 Administer captopril* 12.5mg PO/SL x 1 with MD order 
 Increase blood pressure measurement frequency to q15min until BP has 
partly normalized (sBP = 100-159; dBP = 60-99)  
o Asymptomatic with BP persisting at >180/100 for >60 minutes post-dose, 
despite administering first captopril dose: 
 Consider potential transfer to ER – decision to be made by study 
investigator 
 Administer 2nd dose of captopril 12.5mg x 1 with MD order 
o Management of severe treatment emergent hypertension: 

 
 
 
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 Consider potential transfer to ER – decision to be made by study 
investigator 
 Administer captopril 25mg PO/SL x 1  
 Call 911 immediately for patients experiencing symptoms of a 
hypertensive crisis (e.g., chest paint, shortness of breath) or 
hypertensive encephalopathy (e.g., sudden severe headache, 
visual disturbances, seizures, diminished consciousness, or focal 
neurological deficit) 
o Note: if there are contraindications to captopril, substitute for hydralazine 
10mg PO 
 
In case of development 
of acute anxiety or psychotic symptoms requiring 
pharmacological intervention, the participant will be managed under the care of the onsite 
psychiatrist. The participant may be discharged from the clinic when, in the opinion of the 
investigator, the condition has stabilized. The participant will be accompanied home. The 
participant is to notify the site when they have returned home safely. In the absence of 
receiving a phone call, site staff will directly contact the participant.  
 
Information for how to manage subjects during difficult psychological states are detailed 
in the Yale Manual for Psilocybin-Assisted Therapy of Depression. All therapists will 
undergoing training with the study investigator using this manual. 
 
5.7 
Packaging 
Where applicable, the risperidone 1 mg will be provided be provided and packaged by 
CAMH pharmacy. The psilocybin will be provided by Filament Health Corp (Burnaby, 
British Columbia, Canada). The dose of psilocybin used in this study will be 25mg. The 
entire shipment for this trial will be sent in bulk (i.e. 20 capsules x 25mg each). Psilocybin 
capsules will be packaged individually in high-density polyethylene bottles (30cc). The 
dose for each participant will be stored in individual boxes labelled with the protocol 
number, trial name, lot number, unique box number, and a statement that the drug is for 
clinical use only. The IP will only be removed from the safe for one participant at a time 
on the day of their session. For a description of safety reporting, please see Section 8.3.1 
of the protocol.  
 
5.8 
Blinding of Study Intervention 
Not applicable. 

 
 
 
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5.9 
Receiving, Storage, Dispensing and Return 
5.9.1 
Receipt of Study Intervention Supplies 
Upon receipt of the study intervention supplies, an inventory will be performed and a 
receipt log filled out and signed by the person accepting the shipment. Designated 
research staff/pharmacy must count and verify that the shipment contains all the items 
noted in the shipment inventory.  Any damaged or unusable study intervention in a given 
shipment (active drug or comparator) will be documented in the clinical trial files.   
5.9.2 
Storage 
The risperidone will be stored with CAMH pharmacy. All psilocybin  will be kept in a locked 
area with limited access. The high-density polyethylene (HDPE) bottles of psilocybin  are 
to be stored as indicated in the investigators brochure. Bottles must be maintained at 
room temperature (15 to 30 degrees Celsius) in a locked, secure location within research 
pharmacy. Deviations of storage temperature outside this required range should be 
documented and the study investigator should be notified immediately. Bottles of 
psilocybin should not be frozen. If any component of the psilocybin is damaged, the PI 
must be notified immediately. Any storage deviations that meet criteria for reporting will 
be reported to the REB as a protocol deviation.  
5.9.3 
Dispensing of Study Intervention 
Each participant in Group 1 will be assigned either 1 treatment bottle containing 1 capsule 
of 25mg of psilocybin. Each participant in Group 2 will be assigned  one treatment bottle 
containing 1 tablet of 1 mg of risperidone and one treatment bottle containing 1 capsle of 
25 mg of psi;locybin. For Participants in Group 2, the risperidone will be administered first, 
followed 60-minutes later by psilocybin. The IP will be dispensed and administered to the 
participants only by an appropriately qualified study therapist or delegated clinician. The 
study intervention will be administered orally, with water. First, risperidone will be 
administered followed 60-minutes later by psilocybin. The psilocybin capsules should be 
administered in an unaltered state, by mouth, with water. The capsules should not be 
opened, chewed, or held in the mouth for an extended period without swallowing.  
 
The investigator must keep an accurate accounting of the number of psilocybin capsules   
delivered to the site, and the IPs administered to participants, and destroyed during and 
at the completion of the study. The IPs (psilocybin and risperidone) is to be used in 
accordance with the protocol by participants. The study team, overseen by the PI, should 
maintain records that adequately document that the participants were administered the 
IPs dose specified by the protocol.  
 
Regular study intervention reconciliation will be performed to document study intervention 
assigned, consumed, and remaining. This reconciliation will be logged on an 
accountability log (i.e. drug accountability log), and signed and dated by delegated 
research and/or pharmacy staff. 

 
 
 
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5.9.4 
Return or Destruction of Study Intervention 
At the completion of the clinical trial, there will be a final reconciliation of the study 
intervention shipped, consumed and remaining. This reconciliation will be logged on an 
accountability form, and signed and dated by delegated research and/or pharmacy staff.  
Any discrepancies noted will be investigated, resolved, and documented prior to 
destruction of unused study intervention. Intervention destroyed on site will be 
documented in the clinical trial’s files. 
 
6.0 RESEARCH PROCEDURES 
6.1 
Research Visits 
 
Description of Measures 
 
Screening Measures 
 
Structured Clinical Interview for DSM-5 (SCID-5). The SCID-5 is a semi-structured 
diagnostic interview for ascertaining DSM-5 diagnoses. It will be administered by a trained 
study staff member.  
 
Hamilton Depression Rating Scale (HamD-17). HamD-17 is a clinician-rated measure of 
depressive symptoms that consists of 17 items rated using a semi-structured interview. 
Eight of the 17 items are rated on a 5-point scale (0=absent; 1=doubtful or mild; 2=mild 
to moderate; 3=moderate to severe; 4=very severe), while the remaining 9 items are rated 
on a 3-point scale (0=absent; 1=doubtful or mild; 2=clearly present), yielding a minimum 
total score of 0 (least severe) and a maximum score of 52 (most severe) (Hamilton, 1960).  
 
Safety Measures 
Columbia-Suicide Severity Rating Scale (C-SSRS): The C-SSRS will be used to assess 
suicide potential or tendency as a study entry criteria and monitored throughout the study. 
The C-SSRS is a semi-structured interview designed to assess the severity and intensity 
of suicidal ideation, suicidal behavior, and non-suicidal self-injurious behavior over a 
specified time period. The measurement of suicidal ideation is based on 5 “yes” or “no” 
questions with accompanying descriptions arranged in order of increasing severity. If the 
patient answers “yes” to either questions 1 or 2, the intensity of ideation is assessed in 5 
additional questions related to frequency, duration, controllability, deterrents, and reasons 
for the most severe suicidal ideation. Suicidal behavior is assessed by asking questions 
categorizing behaviors into actual, aborted, and interrupted attempts; preparatory 
behavior; and non-suicidal self-injurious behavior. If any item(s) on the C-SSRS are 
answered “yes”, the primary investigator or physician investigator must review the 
patient’s responses in order to: 
(a) During the screening period and at Baseline to determine the patient’s study 
eligibility and potential need for referral to a mental health professional, and  

 
 
 
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(b) During the study evaluate the patient’s need for appropriate medical management 
such as a referral to a mental health professional.  
 
 
Outcome Measures: 
 
Clinical Global Impression scale (CGI). The CGI is a brief observer-rated instrument that 
measures the clinician’s view of the patient’s global functioning prior to and after initiating 
a study medication. It consists of two one-items measures that evaluate 1) severity of 
psychopathology from 1 (‘normal – not at all ill, symptoms of disorder not present in the 
past seven days’) to 7 (‘among the most extremely ill patients – pathology drastically 
interferes in many life functions;) and 2) change from the initiation of treatment on a similar 
seven-point scale (1 = ‘very much improved’ and 7 = ‘very much worse’). It has been used 
in both research and clinical practice (Busner & Targum, 2007).  
 
Generalised Anxiety Disorder 7-item (GAD-7) scale. The GAD-7 is a brief self-report 
measure of generalised anxiety, it consists of 7 items rated from 0 (‘not at all sure’) to 3 
(‘nearly every day’). It has good psychometric properties and is a widely used research 
instrument in assessing adult anxiety (Spitzer et al., 2006).  
 
Montgomery-Åsberg Depression Rating Scale (MADRS;(Montgomery & Asberg, 1979)). 
The MADRS is a clinician rated measure of severity of depressive symptoms. It consists 
of 10-items rated from 0 to 6. It is one of the most widely used clinician-rated 
assessments of depressive severity with well-established psychometric properties.   
 
Snaith-Hamilton Pleasure Scales (SHAPS). The SHAPS is a 14-item self-report scale 
that measures hedonic capacity. Participants are asked to rate themselves on a Likert 
scale from 0 (‘strongly disagree’) to 3 (‘strongly agree’). It is both a reliable and valid 
measure that is frequently used in research and clinical settings (Snaith et al., 1995). 
 
Stanford Expectancy of Treatment (SETS). The SETS is an instrument to measure 
positive and negative treatment expectancies in clinical trials. It contains two subscales 
for both negative and positive expectancies. There are 6-items which are participant 
rated from ‘strongly disagree’ to ‘strongly agree’. Items 7 to 10 are direct questions 
asked to the participant (Younger et al., 2012) 
World Health Organization Quality of Life Questionnaire – Brief Version (WHO-QoL – 
Bref). This 26-item, self-report measure was developed by the WHO in order to assess 
quality of life in the following areas: physical, psychological, level of independence, social 
relationships, environment, and spirituality/religion/personal beliefs. Responses are rated 
on a 5-point Likert scale rating from 1 = (not at all, over poor, very dissatisfied, never) 
through to 5 = (very good, very satisfied, an extreme amount, completely, always).  
 

 
 
 
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Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS). The WEMWBS consists of a 
12-item scale used to assess the mental wellbeing of people. The self-report scale 
consists of positively worded statements covering feelings and functioning aspects of 
mental wellbeing. Responses are rated on a 5-point Likert scale ranging from 1 (‘none of 
the time’) to 5 (‘all of the time’).  
 
Five Dimensions of Altered States of Consciousness (5D-ASC). The 5D-ASC is a 94-item 
scale that consists of five subscales: 1) oceanic boundlessness; 2) anxious ego 
dissolution; 3) visionary re-structuralization; 4) auditory alterations; 5) reduction of 
vigilance (Dittrich, 1998; Studerus et al., 2010). It is well validated and widely used to 
characterize the subjective effects of psychedelic drugs. This self-rated scale appears as 
at 10-item Likert scale ranging from 1 to 10.  
 
 
Outline of Study Procedures 
 
Visit 1 (V1) – Screening Visit   
o Administered by trained study staff: 
 Informed consent 
 Review of medical history, family medical history, and demographics 
 ATHF 
 SCID-5 
 HamD-17 
 Vital Signs (blood pressure, pulse) 
 Height and weight 
o Clinician administered: 
 Review of prior and current medications; the participant will be tapered from 
prohibited medications (see Section 5.6), if any, under the supervision of the 
study clinician 
• The study clinician will discuss options of tapering off medications with 
the participant and their healthcare provider.  
• Participants will be given a choice of how quickly they would like to come 
off the medications, but participants must be off concomitant medications 
(see Section 5.6) at least 2 weeks prior to the Baseline Visit (V2). Some 
medications may require a longer tapering period.  
 Review of eligibility criteria, medical history, and family medical history 
 Review of assessments 
 Documentation of contraceptive method to be used by the participant 
 C-SSRS 
 
o Biological specimen collection and laboratory evaluations collected at the Queen 
Street CAMH laboratory:  
 Clinical laboratory tests: 
• Approximately 20 mL blood will be drawn to conduct the following 
evaluations: 

 
 
 
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• Haematology: hemoglobin, hematocrit, red blood cell count, mean 
corpuscular hemoglobin, mean corpuscular volume, mean corpuscular 
hemoglobin concentration, white blood cell count (with differential), and 
platelet count. 
• Chemistry: albumin, alkaline phosphatase, alanine aminotransferase 
(ALT), amylase, aspartate aminotransferase (AST), bicarbonate, bilirubin 
(direct, indirect, and total), calcium, chloride, creatine kinase, creatinine, 
gammaGT, glucose, lactate, dehydrogenase, lipase, magnesium, 
phosphate, potassium, protein-total, sodium, urea (blood urea nitrogen), 
and uric acid. 
 Urine Samples: 
• Urinalysis: a dipstick urinalysis will be performed for blood, glucose, 
ketone, protein, pH, specific gravity, nitrite, leukocytes, bilirubin, and 
urobilinogen 
• Urine drug screen: for illicit drugs or drugs of abuse. Results of a positive 
drug screen will be reviewed by the study clinician for pattern of use.  
• Urine pregnancy test for all women/people of childbearing potential 
 ECG: Standard 12-lead ECG to check heart function 
 
 
Washout Period: Minimum of 2-Weeks  
Participants who are on concomitant medications (Section 5.6) must be tapered off at 
least 2 weeks prior to Baseline (V2). The plan for tapering off medications will be 
determined at the first screening visit (V1) with the participant and the study physician. 
During the washout period, the study physician will have weekly appointments with the 
participant to check how they are doing and ensure they are safe. The weekly 
appointments can be scheduled in-person or remote (via telephone/WebEx) based on 
the participant’s preference and at the discretion of the study physician. Participants will 
be assessed for suicidality with the C-SSRS at each contact/visit. 
 
Any safety assessment visits during the washout period will be called V1a, V1b, etc. 
During these visits, the C-SSRS and any changes in medications since the previous 
visit will be obtained in addition to other assessments at the study clinician’s discretion.  
 
Visit 2A (V2A)- Imaging Visit- between Visit 1 and Visit 2B 
Visit 2A will occur at any time after Visit 1- Screening and Visit 2B-Baseline, depending 
on participant preference and appointment availability.  
o A [18F]SynVesT-1 scan with arterial line will be performed by CAMH imaging staff at the 
CAMH CAMH Brain Health Imaging Centre (250 College Street), as well as an MRI scan 
(1 hour).  
o Note: The PET scan and MRI scan can be performed on the same day or 
separated into different days, depending on participant preference and 
appointment availability. The MRI scan must occur within 2 weeks of the PET scan.  
 

 
 
 
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Visit 2B (V2B) - Baseline Visit  - Day -7 to Day -1 
The Baseline visit (V2) will occur approximately 2-6 weeks after the initial Screening 
(V1) when the participant has successfully been tapered off any concomitant 
medication. At the Baseline Visit (V2), the participant’s eligibility will be confirmed by the 
study investigator by reviewing the Inclusion/Exclusion Criteria (Section 4.4) and 
updating the medical history. The Baseline visit (V2) can occur within 7 days before the 
anticipated psilocybin session and may be split over multiple days to reduce the burden 
on the participant (additional study visits will be labelled V2a, V2b etc). The following 
procedures will be performed and recorded at the Baseline visit (V2): 
o Administered by trained study staff: 
 Vital Signs (blood pressure, heart rate) 
 C-SSRS 
 CGI 
 GAD-7 
 MADRS 
 SETS 
 SHAPS 
 WHOQOL-BREF 
 WEMWBS 
o Clinician administered: 
 Confirmation of eligibility criteria  
o Optional laboratory evaluations collected at the Queen Street CAMH laboratory:  
• Blood: 20 mL of blood will be withdrawn under fasting conditions 
(minimum 6-hour fast) from participants. The plasma will be separated 
by centrifuging the blood at 1500 rpm for 10 min at 4°C, and 
subsequently stored at -80°C for future analysis. This is optional for all 
participants.  
o Biomarkers:  
 Mitochondrial biomarkers: (1) circulating cell-free mitochondrial DNA 
(ccf-mtDNA): We will use the QIAmp 96 DNA Blood kit (Qiagen, 
Valence, USA) to extract DNA from 200μL of the plasma, according to 
manufacturer protocols for blood and body fluids. The total DNA will be 
quantified using spectrophotometric analysis at 260/280 nm in 
NanoPhotometer ® P-Class (Implen, Westlake Village, CA, US). 
Quantitative analysis of the ccf-mtDNA will be performed using a real-
time polymerase chain reaction (RT-PCR). The PCR reaction will be 
performed using SYBR Green Technology (Thermo Fisher Scientific, 
Waltham, MA, USA). Each 20 μL reaction contained 5 μL of template, 1 
μL of each primer (10 μM), 10 μL SYBR MIX (2× Sensifast, Bioline, 
London, UK), and 3 μL of nuclease-free water. Each reaction will be run 
in triplicate on CFX96 Touch Real-Time PCR Detection System (Bio-
rad, Hercules, California, USA). PCR program: initial denaturation at 95 
◦C for 10 min, followed by 45 cycles consisting of 95 ◦C in 10 s 
(melting), 65 ◦C for 10 s (annealing), and 72C for 10sec (extension). 
The program ended with a melting curve analysis measuring 

 
 
 
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fluorescence continuously from 60 to 97 ◦C. We will use primers to 
amplify the mtDNA genes MT-ND1 and MT-ND4, as well as nuclear β-2 
microglobulin.  
 (2) mtDNA next-generation sequencing: Genomic DNA will be purified 
from blood samples (10 ml) (ChemagicTM MSM I DNA extractor; 
Perkin-Elmer, Waltham, MA) following manufacturer protocol. Briefly, 
whole mtDNA will be amplified in one large fragment of 16.6kb in length 
using long-range polymerase chain reaction approach. The mtDNA next 
generation sequencing (NGS) will be performed on Illumina MiSeq v3 
device using 2x300 read length. Libraries will be prepared using 
standard Illumina DNA Preparation for NGS. The CAMH Biobank team 
will prepare the samples (pre-sequencing preparation), and send them 
to the Ontario Institute for Cancer Research facility for DNA 
sequencing.We will use in-house pipeline for raw data cleaning and 
variant call. (3) mtDNA-copy number: The mtDNA copy number will be 
assayed using the relative quantification method using a mtDNA 
amplicon and a nuclear single copy gene (β-2 microglobulin). The ratio 
of mtDNA to nuclear DNA will be quantified by 2−ΔCt method using 
primers for mtDNA and nuclear β-2 microglobulin as well as thermal 
cycler condition as standard. All qPCR will be performed on the BioRad 
CFX96 RT-PCR detection system (Bio-Rad Laboratories, Inc.). Each 
sample will be run in triplicate using 0.6ng of DNA in a 20μl reaction. 
The PCR reactions will be performed on separate runs with the same 
samples in the same well positions. Primers will be the same as 
describe for ccf-mtDNA. 
 Neuroinflammation markers: Brain Derived Neurotrophic Factor (BDNF) 
and Inflammatory Cytokines,  
 Plasma levels of Tryptophan, 5-HT and Kynurenine 
 
 Urine drug screen: for illicit drugs or drugs of abuse. Results of a positive 
drug screen will be reviewed by the study clinician for pattern of use.  
 Urine pregnancy test for all women of childbearing potential 
o The Pre-Psilocybin Neurophysiology visit  will occur at Baseline (V2B), within 7-days 
of Psilocybin Session Dose (V3). Neurophysiology procedures will be reviewed with 
participant prior to the following procedures being performed and recorded: 
Administered by trained study staff with a responsible Clinician available on site: 
 Assessment of TMS contraindications 
 Assessment of participant’s resting motor threshold (RMT) 
 TMS-EEG stimulating left FC (SICI Paradigm) 
 
o Preparatory session (up to 4 hours) with the study therapists which will involve 
building a therapeutic alliance, psychoeducation about the psychedelic experience, 
and setting intentions for the intervention.  
 Documentation of participant preference and consent for therapeutic touch 
 Note: Therapists will have the option to schedule an additional preparatory 
session at their discretion.  

 
 
 
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 For a more detailed explanation of the preparatory therapy session, please 
refer to the Yale Manual for Psilocybin-Assisted Therapy of Depression. 
 Prep therapy can occur in-person or via secure videoconferencing software 
(i.e. WebEx). 
 
o Clinical Laboratory Tests: 
 
ECG 
 
Urine Drug Screen 
 
Visit 3 (V3) – Intervention – Day 0  
The intervention will occur the day after Baseline (V2). The participant may have this 
session ≤7 days following the Baseline visit (V2). If the participant is out of the ≤7 day 
window, all baseline assessments are to be repeated. On the day of the intervention the 
following procedures will take place: 
o Review and confirmation of participant preference and consent for therapeutic touch 
o Review of neurophysiology tests with participant prior to dosing 
o Study intervention administration (Section 5.0): 1 oral dose of 1mg of risperidone, 
followed 60-minutes later by 1 oral dose of 25mg of psilocybin, or 1 oral dose of 
25mg of psilocybin alone, administered in conjunction with supportive therapy 
(PAP).  
o Vital signs (body temperature, blood pressure and pulse) will be taken three times 
during this session (once prior to psilocybin administration, once at one hour post- 
administration and once at the end of the intervention session).  
o At least one therapist will be present in the room at all times during PAP and be 
available to respond to participants’ physical and emotional needs 
o Participants will be instructed to lie on a bed in a non-clinical environment, and 
therapists will encourage participants to focus their attention inward and stay with 
any experience that arises. To enhance inward reflection, a pre-selected music 
playlist will be played. Administration of questionnaires or other instruments to be 
completed at the end of the dosing session when the acute effects of psilocybin 
have resolved:  
 Study team or therapist administered: 
• 5D-ASC to assess the acute drug effects using 5 primary dimensions and 
respective sub dimensions.  
• C-SSRS 
 
Neurophysiology Testing: (Administered by trained study staff with a responsible 
clinician available on site): 
• 
1 measurement approximately 1-2 hours after psilocybin administration 
• 
1 measurement at the end of the visit 
o The participant will be discharged 5-6 hours post-dosing when, in the opinion of the 
study PI (or delegate), the acute effects of psilocybin are resolved. The participant 
must be accompanied home by a caregiver who will remain with them for up to 24hrs 
after the dose was administered. 
o Rescue medications are permitted during this visit as outlined in Section 5.6.  

 
 
 
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Visit 4 & Visit 5 (V4 & V5) – Post-Intervention – Day 1 & Day 7 
o Administered by trained study staff or therapist/clinician: 
 CSSRS 
 CGI 
 MADRS 
 SHAPS 
o Integrative psychotherapy session will occur with the study therapists. The 
participant will discuss their experience during the dose session including their 
thoughts, feelings, and experiences. Integration therapy can occur in-person or via 
secure videoconferencing software (i.e. WebEx). For more detailed information on 
the integrative therapy sessions, please refer to the therapists manual (Yale Manual 
for Psilocybin-Assisted Therapy of Depression). 
On Visit 4 (V4) only 
o Optional biological specimen collection and laboratory evaluations collected at the 
Queen Street CAMH laboratory:   
• Blood: 20mL of blood will be withdrawn under fasting conditions 
(minimum 6-hour fast). The plasma will be separated by centrifuging the 
blood at 1500 rpm for 10 min at 4°C, and subsequently stored at -80°C 
for future analysis. This is optional for all participants.  
o Biomarkers:  
o Mitochondrial biomarkers: (1) circulating cell-free mitochondrial DNA (ccf-
mtDNA): We will use the QIAmp 96 DNA Blood kit (Qiagen, Valence, USA) 
to extract DNA from 200μL of the plasma, according to manufacturer 
protocols for blood and body fluids. The total DNA will be quantified using 
spectrophotometric analysis at 260/280 nm in NanoPhotometer ® P-Class 
(Implen, Westlake Village, CA, US). Quantitative analysis of the ccf-mtDNA 
will be performed using a real-time polymerase chain reaction (RT-PCR). 
The PCR reaction will be performed using SYBR Green Technology 
(Thermo Fisher Scientific, Waltham, MA, USA). Each 20 μL reaction 
contained 5 μL of template, 1 μL of each primer (10 μM), 10 μL SYBR MIX 
(2× Sensifast, Bioline, London, UK), and 3 μL of nuclease-free water. Each 
reaction will be run in triplicate on CFX96 Touch Real-Time PCR Detection 
System (Bio-rad, Hercules, California, USA). PCR program: initial 
denaturation at 95 ◦C for 10 min, followed by 45 cycles consisting of 95 ◦C 
in 10 s (melting), 65 ◦C for 10 s (annealing), and 72C for 10sec (extension). 
The program ended with a melting curve analysis measuring fluorescence 
continuously from 60 to 97 ◦C. We will use primers to amplify the mtDNA 
genes MT-ND1 and MT-ND4, as well as nuclear β-2 microglobulin.  
o (2) mtDNA next-generation sequencing: Genomic DNA will be purified from 
blood samples (10 ml) (ChemagicTM MSM I DNA extractor; Perkin-Elmer, 
Waltham, MA) following manufacturer protocol. Briefly, whole mtDNA will be 
amplified in one large fragment of 16.6kb in length using long-range 
polymerase chain reaction approach. The mtDNA next generation 
sequencing (NGS) will be performed on Illumina MiSeq v3 device using 
2x300 read length. Libraries will be prepared using standard Illumina DNA 

 
 
 
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Preparation for NGS. The CAMH Biobank team will prepare the samples 
(pre-sequencing preparation), and send them to the Ontario Institute for 
Cancer Research facility for DNA sequencing.We will use in-house pipeline 
for raw data cleaning and variant call. (3) mtDNA-copy number: The mtDNA 
copy number will be assayed using the relative quantification method using 
a mtDNA amplicon and a nuclear single copy gene (β-2 microglobulin). The 
ratio of mtDNA to nuclear DNA will be quantified by 2−ΔCt method using 
primers for mtDNA and nuclear β-2 microglobulin as well as thermal cycler 
condition as standard. All qPCR will be performed on the BioRad CFX96 
RT-PCR detection system (Bio-Rad Laboratories, Inc.). Each sample will be 
run in triplicate using 0.6ng of DNA in a 20μl reaction. The PCR reactions 
will be performed on separate runs with the same samples in the same well 
positions. Primers will be the same as describe for ccf-mtDNA. 
o Neuroinflammation markers: Brain Derived Neurotrophic Factor (BDNF) and 
Inflammatory Cytokines 
o Plasma levels of Tryptophan, 5-HT and Kynurenine 
 
 
o On Visit 5 (V5) only, post-psilocybin neurophysiology assessments will be 
completed. The following procedures will be performed and recorded: 
Administered by trained study staff with a responsible Clinician available on site: 
 TMS-EEG (Visit 5 only) (Allowable window of +/- 3 days in case of scheduling 
issues) 
 
Visit 5B (V5B)- Follow-up Imaging Visit  
 
• 
A post-treatment [18F]SynVesT-1 scan with arterial line will be performed by CAMH 
imaging staff at the CAMH Brain Health Imaging Centre (250 College Street).  
• 
This post-treatment scan can take place between 1 and 6 weeks after treatment 
administration.  
 
 
Visit 6 (V6), Visit 7 (V7) & Visit 8 (V8) – Follow-Up: Week 2, Week 3 & Week 4 
Follow-up visits occur at Weeks 2 (V6), 3 (V7), and 4 (V8) after the intervention. The 
following assessments will occur at each visit: 
o Administered by trained study staff or clinician: 
 CSSRS 
 CGI 
 GAD-7 (except Visit 7) 
 MADRS 
 SHAPS  
 WHOQOL-BREF (except Visit 7) 
 WEMWBS (except Visit 7) 
o Clinician administered: 
 
Review of safety assessments 

 
 
 
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6.2 
Schedule of Events 
 
Procedures 
Screening (Visit 1) 
Washout period1 
(2-6 weeks) 
Visit 2A (V2A)- 
Imaging Visit- 
between Visit 1 and 
Visit 2B 
Baseline2 (Visit 2B, 
Day -7 to Day -1) 
Intervention (Visit 
3, Day 0) 
1-Day Post-
Intervention (Visit 4, 
Day 1) 
1-Week Post-
Intervention (Visit 
5A, Day 7) 
Visit 5B (V5B)- 
Follow-up Imaging 
Visit 
2-Weeks Post-
Intervention (Visit 6, 
Day 14) 
3 Weeks Post
Location of Visit 
Clinic 
Clinic or 
Remote 
CAMH 
Imaging 
Centre 
Clinic 
Clinic 
Clinic 
Clinic 
CAMH 
Imaging 
Centre 
Clinic or 
Remote 
C
R
Allowable Window 
 
Weekly 
 
 
≤7 days from 
Baseline 
None
 
±3 day 
 
±3 day 
Informed Consent 
✔ 
 
 
 
 
 
 
 
 
 
Demographics 
✔ 
 
 
 
 
 
 
 
 
Medical history 
✔ 
 
 
✔ 
 
 
 
 
 
Prior/concomitant medication 
review 
✔ 
 
 
✔ 
✔ 
✔ 
✔ 
 
✔ 
Inclusion/Exclusion Criteria Review 
✔ 
✔ 
 
✔ 
 
 
 
 
 
ATHF 
✔ 
 
 
 
 
 
 
 
 
CGI 
 
 
 
✔ 
 
✔ 
✔ 
 
✔ 
CSSRS3 
✔ 
✔ 
 
✔ 
✔ 
✔ 
✔ 
 
✔ 
HamD-17 
✔ 
 
 
 
 
 
 
 
 
MADRS 
 
 
 
✔ 
 
✔ 
✔ 
 
✔ 
SCID-5 
✔ 
 
 
 
 
 
 
 
 
Vital signs (blood pressure, pulse) 
✔ 
 
 
✔ 
✔ 
 
 
 
 
Vital signs (body temperature) 
 
 
 
 
✔ 
 
 
 
 
Weight 
✔ 
 
 
 
 
 
 
 
 
Height 
✔ 
 
 
 
 
 
 
 
 
ECG 
✔ 
 
 
 
 
 
 
 
 

 
 
 
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Clinical laboratory tests4 
✔ 
 
 
✔ 
 
✔ 
 
 
 
Urinalysis 
✔ 
 
 
 
 
 
 
 
 
Urine drug screening 
✔ 
 
 
✔ 
 
 
 
 
 
Urine pregnancy test5 
✔ 
 
 
✔ 
 
 
 
 
 
Documentation of birth control 
✔ 
 
 
 
 
 
 
 
 
Preparatory/Integrative therapy & 
psychoeducation6 
 
 
 
✔ 
✔ 
✔ 
✔ 
 
 
Intervention (1mg of risperidone + 
25mg of psilocybin / 25mg of 
psilocybin) 
 
 
 
 
✔ 
 
 
 
 
Neurophysiology  (TMS-EEG)  
 
 
 
✔ 
✔ 
 
✔ 
 
 
Adverse event and serious adverse 
event review and evaluation 
✔ 
✔ 
 
✔ 
✔ 
✔ 
✔ 
 
✔ 
Source documentation & CRF 
completion 
✔ 
✔ 
 
✔ 
✔ 
✔ 
✔ 
 
✔ 
5D-ASC7 
 
 
 
 
✔ 
 
 
 
 
GAD-7 
 
 
 
✔ 
 
 
 
 
✔ 
SETS 
 
 
 
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SHAPS 
 
 
 
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✔ 
✔ 
 
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WEMWBS 
 
 
 
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✔ 
WHO-QOL-BREF 
 
 
 
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✔ 
Pre-Treatment PET scan9 
 
 
✔ 
 
 
 
 
 
 
MRI9 
 
 
✔ 
 
 
 
 
 
 
Post-Treatment PET scan8  
 
 
 
 
 
 
 
✔ 
 
1. 
Additional visits may be needed during the w ashout period to ensure adequate time for discontinuation of medication. Visits w ill occur on a w eekly basisduring 
this period (V1a, V1b, etc.). Review  of medications and assessments for suicidality w ill occur in addition to other assessments at the discretion of the study 
investigator. 
2. 
Baseline assessments can occur on separate days (≤7 days from the day of the intervention) to reduce the burden on participants. These visits w ill be V2a, 
V2b etc. 
3. 
The “Last 12 Months” version w ill be administered at Screening and the “Since Last Visit” version w ill be administered at all other visits.  
4. 
See Section 6.0: Research Procedures for complete list of required laboratory tests to be performed. 
5. 
For w omen/females and people of child-bearing age only 
6. 
Additional therapy visits may be scheduled at the discretion of the study therapists and/or the study investigator and prep as w ell as integration therapy can 
occur in-person or via WebEx. 
7. 
To be administered immediately after the acute effects of psilocybin have subsided. 
8. 
Can be administered anytime betw een 1-6 w eeks post intervention administration (Visit 3) 
9. 
Can be administered anytime betw een Screening (Visit 1) and Baseline (Visit 2) 

 
 
 
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Instruments: 
ATHF: Antidepressant Treatment History Form; CGI: Clinical Global Impression; CSSRS: Columbia Suicide Severity Rating Scale; ECG: Electrocardiogram; GAD-7: Generalized 
Anxiety Disorder assessment form; HamD-17: Hamilton Depression Rating Scale; MADRS: Montgomery-Asberg Depression Rating Scale; SCID-5: Structured Clinical Interview for 
DSM-5; SETS: Stanford Expectations of Treatment Scale; SHAPS: Snaith Hamilton Anhedonia Scale; WEMWBS: Warwick-Edinburgh Mental Wellbeing Scale; WHO-QoL-BREF: 
World Health Organization Quality of Life abbreviated scale; 5D-ASC: 5-Dimensional Altered States of Consciousness Rating Scale. 

 
 
 
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7.0 STATISTICAL PLAN 
7.1 
Sample Size Determination 
A formal sample size calculation was not conducted for the purposes of this 
feasibility/pilot study. We believe that the proposed sample of N = 12 participants will be 
suitable to establish feasibility to inform the development of a larger, adequately 
powered PET imaging study.  
7.2 
Statistical Methods 
Characteristics of the trial cohort will be summarized by mean (SD), median (minimum, 
maximum). Summary raw scores will be presented at each assessment time both 
numerically and graphically. The small sample size means that conservative 
nonparametric testing is required in order to address the primary and secondary 
objectives. Exact paired permutation t-tests will be used to determine whether 
psilocybin-assisted psychotherapy with or without risperidone achieves a 50% reduction 
in MADRS. 
 
PET analyses will be conducted using the region of interest (ROI) method in the PMOD platform. 
This software, in concert with SPM, (i) transforms a standard brain template with a set of 
predefined ROIs to match individual high-resolution MR images, (ii) refines the ROIs from the 
transformed template based on the gray matter probability of voxels in the individual MR images 
(segmentation step), and (iii) co-registers the individual MR images to the PET images so that 
the individual refined ROIs are transformed to the PET image space. The ROI template is based 
on the anatomical Hammers brain atlas(Hammers et al., 2003) as well as cytoarchitecturally-
defined PFC subregions developed by Rajkowska(Chiuccariello et al., 2014; Rajkowska & 
Goldman-Rakic, 1995). 
 
The primary ROIs are the hippocampus and prefrontal cortex subdivisions, the dorsolateral 
prefrontal cortex, orbitofrontal cortex, and medial prefrontal cortex. PET outcome measures 
include volume of distribution, VT (primary outcome measure), and binding potential, BPND 
(secondary outcome measure). These will be determined within each ROI at each time point 
using arterial plasma input functions and the one-tissue compartment model (Naganawa et al., 
2021). In the case that arterial blood sampling data is not available, data will be analyzed using 
SRTM2 to generate estimates of BPND (Naganawa et al., 2022). 
 
Statistical analysis will be performed in R software. Change in synaptic density 
([18F]SynVesT-1) from pre- to post-treatment will be compared within subjects using a 
mixed effects linear model with subject as a random effect factors and ROI and session 
(baseline vs. post-treatment) as fixed effects. Post hoc paired t tests will assess 
synaptic density changes in each of the primary ROIs. Effects will be considered 
significant at the threshold of p < 0.05. Exploratory analyses will be performed in other 
brain regions relative to MDD and psilocybin treatment including hypothalamus, 
amygdala, and insula, as well as in voxel-wise whole brain analyses in order to identify 
other relevant regions and guide inquiry in a future, fully-powered study. 
 
 

 
 
 
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8.0 SAFETY AND ADVERSE EVENTS 
8.1 
Definitions 
Adverse Event 
An adverse event (AE) is any untoward medical occurrence in a research participant 
administered an investigational product and which does not necessarily have a causal 
relationship with this treatment. An adverse event (AE) can therefore be any unfavourable 
and unintended sign (including an abnormal laboratory finding), symptom, or disease 
temporally associated with the use of a medicinal (investigational) product, whether or not 
related to the investigational product.   
 
AE severity can be defined as: 
• 
Mild: discomfort noticed but no disruption of normal activity 
• 
Moderate: discomfort sufficient to reduce or affect normal daily activity 
• 
Severe: interferes significantly with the participant’s normal activity or course of illness 
 
Serious Adverse Event 
A serious adverse event (SAE) is any AE that is:  
• Fatal; 
• Life-threatening; 
• Requires or prolongs hospital stay; 
• Results in persistent or significant disability or incapacity; 
• A congenital anomaly or birth defect; or 
• An important medical event (events that may not be life threatening but are of major 
clinical significance, such as a drug overdose or seizure that did not result in in-patient 
hospitalization).  
 
Adverse Drug Reactions 
An adverse drug reaction is any noxious, unintended or undesirable response to a 
medicinal product related to any dose.  
 
Unexpected Adverse Reactions 
An adverse reaction, the nature or severity of which is not consistent with the applicable 
product information (e.g. Investigator’s Brochure).  
 
Adverse Event Collection Period 
AEs occurring as of the first screening visit and until the end of the study will be collected. 
AEs recorded during this period will be followed through to resolution, or until the event 
is assessed as chronic or stable.  
 
Preexisting Condition 
A preexisting condition is one that is present at the start of the clinical trial.  A preexisting 
condition will be recorded as an adverse event if the frequency, intensity, or the character 
of the condition worsens during the study period. At the Screening Visit (V1), any clinically 

 
 
 
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significant abnormality will be recorded as a preexisting condition in source 
documentation. Where applicable and at the consent of the participant, additional 
information from the participant’s healthcare provider including medical records, may be 
requested. 
Throughout 
the 
clinical 
trial, 
any 
new 
clinically 
significant 
findings/abnormalities that meet the definition of an adverse event will also be recorded 
and documented as an adverse event.  
 
Post-study Adverse Event 
At the last scheduled visit, the PI and/or QI should instruct each participant to report any 
subsequent event(s) that the participant believes might reasonably be related to 
participation in this clinical trial.  The PI and/or QI should notify Health Canada of any 
death or adverse event (meeting reporting criteria) occurring at any time after a participant 
has discontinued or terminated participation that may reasonably be related to this clinical 
trial.  Health Canada and Filament Health Corp. should also be notified if the PI and/or QI 
should become aware of the development of cancer or of a congenital anomaly in a 
subsequently conceived offspring of a participant that was involved in this clinical trial.  
 
Abnormal Laboratory Values 
A clinical laboratory abnormality should be documented as an adverse event if any one 
of the following conditions are met:  
• The laboratory abnormality is not otherwise refuted by a repeat test to confirm the 
abnormality; 
• The abnormality suggests a disease and/or organ toxicity; 
• The abnormality is of a degree that requires active management (e.g. change of dose, 
discontinuation of the study intervention, more frequent follow-up assessments, further 
diagnostic investigation, etc.); or 
• Any laboratory abnormalities assessed as being clinically significant by a study 
physician or qualified individual. 
8.2 
Recording of Adverse Events 
All adverse events occurring during the study period must be recorded. At each contact 
with the research participant, the research team must seek information on adverse events 
by specific questioning.  Information on all adverse events should be recorded 
immediately in the data collection form and/or legal health record, and recorded in the 
adverse event log. All adverse events will be assessed the PI for relatedness, 
expectedness, seriousness, and severity in relation to the study intervention. All clearly 
related signs, symptoms, and abnormal diagnostic procedure results should be recorded 
in the data collection form and/or legal health record and assessed by the PI in a timely 
manner allowing sufficient time to meet required reporting timelines for SAEs and 
SUADRs (severe unexpected adverse drug reactions) if needed. Adverse events related 
to the study drug will be reported to Filament Health Corp within 24hrs of the study team 
becoming aware of the event. . These reports should not contain PHI.  

 
 
 
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8.3 
Reporting of Serious Adverse Events 
8.3.1 
Investigator Reporting: Notifying the Sponsor 
The sponsor for this study is CAMH and the PI/QI (Dr. Ishrat Husain), therefore no 
notification is necessary. However, Filament Health Corp. is the supplier of the psilocybin 
used in this trial. Filament Health Corp. will be sent safety reports on adverse events and 
serious adverse events within 24hrs of the study team becoming aware of the event.  
None of these safety reports will contain PHI and all data will be coded.  
 
8.3.2 
Investigator Reporting: Notifying the REB 
The process for notification to the REB for applicable serious adverse events (SAEs) must 
be completed as per REB reporting requirements. SAEs and unanticipated events must 
be recorded and reported to the REB in accordance with the REB’s reporting 
requirements and timelines. Copies of each report and documentation of REB notification 
and REB receipt/acknowledgement must be kept in the Investigator Study Binder. 
 
8.3.3 
Sponsor Reporting of SUADRs: Notifying Health Canada 
The sponsor for this study is CAMH & the study PI/QI. The study PI/QI is responsible for 
reporting the safety information to Health Canada as required. The SUADR report must 
be reported to Health Canada in the following cases: 
• Where the ADR is neither fatal nor life-threatening, within 15 days after becoming 
aware of the information 
• Where it is fatal or life-threatening, immediately where possible and, in any event, 
within 7 days after becoming aware of the information 
• And within 8 days after having informed Health Canada of the ADR, submit as 
complete as possible, a report which includes an assessment of the importance 
and implication of any findings.  
8.3.4 
Sponsor Reporting of SUADRs: Notifying Sites 
Not applicable. 
8.4 
Reporting of Device Deficiencies 
Not applicable. 
8.5 
Safety Management Plan 
 
Safety of the participants (including data confidentiality) and the scientific integrity of the 
project will be ensured by the research team led by the PI. Participant safety will be 
monitored at each study visit by asking the participant about their experience and about 
any adverse events from the last study visit. All adverse events will be reviewed by the 
study PI and reported to the REB and/or Health Canada in accordance with the regulatory 
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outlined in Section 8.2 and 8.3. Safety reports on AEs and SAEs will be provided to 
Filament Health within 24hrs of the study team becoming aware of the event. In addition, 
all safety data related to the psilocybin will be provided to Filament Health. . None of these 
safety reports will contain PHI and all data will be coded. The study team will also use a 
published Suicide Risk Management Protocol to assess and reduce suicide risk (Herbeck 
et al., 2015). Participants experiencing a serious adverse event will be immediately 
withdrawn from the study. In the case of increased suicidality, the study physician will 
conduct an urgent psychiatric assessment with the participant. 
 
The study investigator and study team will meet regularly to review the accrued data, data 
confidentiality, recruitment, and participants complaints. Participant confidentiality will be 
maintained through the use of code numbers to identify all participants. All research 
records will be kept in a locked file and no participants will be identified in any published 
report.  
 
Participants may be removed from the study at the discretion of the PI. Reasons for 
possible withdrawal from the clinical trial are outlined in Section 4.7.1. 
 
Therapeutic Risk Management Measures for Psychological Harm 
Psychological well-being will be closely monitored by the study team and study therapists 
throughout the trial. Study therapists will provide the participant with information about 
what might be experienced during the dosing session, including physiological, sensory 
and psychological effects, and the possibility of challenging experiences. The role of the 
therapists at each of the therapy sessions is to provide support for the participant and 
create a psychologically safe environment.  Therapists will work with the participant to 
develop grounding exercises according to the participant’s preference (e.g., deep 
breathing, breath-focused awareness, progressive muscle relaxation etc.). These 
grounding techniques will be re-reviewed on the day of the intervention. Following dosing, 
integration therapy sessions will be conducted where participants can reflect on their 
dosing experience with the study therapists. For a full description of therapeutic safety 
monitoring procedures, refer to the Yale Manual for Psilocybin-Assisted Therapy of 
Depression. Participants will continue to be followed by the study team for up to 4-weeks 
after the intervention. Psychological well-being (including suicidality) and adverse event 
monitoring will be assessed at all time-points.  
 
 
Remote Assessment Safety Procedures 
All remote assessments will be conducted in a private room. The research team will not 
require identification from the participant as the research team will already be familiar with 
the participant and will be able to identify them visually through WebEx. The sessions 
occuring over WebEx or over the phone will not be recorded. If the assessment requires 
screen sharing, the individual administering the assessment will ensure that any 
documents or windows on the desktop containing PHI or personal information will be 
closed. The individual administering the assessment will also have access to necessary 
communication technology in order to communicate with relevant research supports or 
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remote assessments or communicating via email, the research team will limit personal 
information in all emails by avoiding full names ot direct identifiers in the subject line of 
the email or meeting invitation.  
 
8.6 
Unblinding Procedures 
Not applicable. 
8.7 
Data and Safety Monitoring Board 
 
9.0 CLINICAL TRIAL DISCONTINUATION AND 
CLOSURE 
9.1 
Clinical Trial Discontinuation 
This clinical trial may be temporarily suspended or prematurely terminated if there is 
sufficient reasonable cause (i.e. closure based on PI decision, sponsor/funder decision, 
REB or other oversight bodies’ decision; review of serious, unexpected and related AEs; 
noncompliance; futility). Notification, which includes the reason for study suspension or 
termination, will be provided by the suspending or terminating party to research 
participants, the PI, funding agency, CAMH, and regulatory authorities.  If the clinical trial 
is prematurely terminated or suspended, the PI will promptly inform research participants, 
the REB, and the sponsor, and will provide the reason(s) for the termination or 
suspension. All communication with participants for this purpose will go through REB 
review and approval.  Research participants will then be contacted, as applicable, and be 
informed of changes to the study visit schedule. 
 
10.0 DATA HANDLING AND RECORD KEEPING 
10.1 Source Documents & Case Report Forms 
Source documentation will be recorded in data collection forms. 
We will also collect health card information from all participants that will be securely 
transferred to ICES, which is a prescribed entity under section 45 of Ontario’s Personal 
Health Information Privacy Act that is permitted to collect personally identifiable 
information for the purposes health system management and evaluation without individual 
consent or research ethics approval. The purpose of this transfer will be to link the 
individual’s clinical data with health administrative databases to study long-term safety 
and efficacy outcomes. The maximum access date will be 15 years to evaluate long-term safety 
and efficacy outcomes. 
  
 
REDCap  

 
 
 
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Data for this clinical trial will be managed using REDCap electronic case report forms. 
This system is maintained on central CAMH servers, with data backed up daily, and is 
supported by the Research Informatics department.  
 
10.2 Protocol Deviations 
No deviations from or changes to the protocol will be implemented without approval from 
the REB or Health Canada, unless to eliminate an immediate hazard to a participant. All 
study staff will monitor the study procedures to detect any potential protocol deviations. 
All potential protocol deviations will be reviewed by the study PI. The protocol deviation 
will be reported if any of the following criteria are met: 
• Deviations that, in the opinion of the PI, jeopardize the safety of research 
participants, or that jeopardize the research efficacy or data integrity 
• Any change in the approved process for obtaining consent 
• Any deviations that lead to a serious adverse event or unanticipated problem 
• Any unauthorized collection, use, or disclosure of personal health information (PHI) 
10.3 Record Retention 
Research records pertaining to this clinical trial will be retained for 15 years.  
10.4 Clinical Trial Registration 
In accordance with TCPS 2, a description of this trial will be registered on 
www.clinicaltrials.gov before the start of recruitment activities, and the content will be 
updated throughout the duration of the clinical trial. All results, including negative results 
should be entered at the completion of the clinical trial. 
11.0 STUDY MONITORING, AUDITING, AND 
INSPECTING 
11.1 Study Monitoring Plan 
Site monitoring is conducted to ensure that the rights and well-being of research 
participants are protected, the reported trial data are accurate, complete, and verifiable, 
and the conduct of the clinical trial is in compliance with the currently approved 
protocol/amendment(s), ICH GCP, and applicable regulatory requirement(s). Reference 
the study monitoring plan for specific monitoring information.  
 
11.2 Auditing and Inspecting  
 
The PI and site will permit study-related audits, and inspections by the REB, CAMH, 
sponsor, and applicable granting agencies or regulatory bodies, including access to all 
study-related documents (e.g. source documents, regulatory documents, data collection 
instruments, study data, etc.). The PI will ensure the capability for audits/inspections of 

 
 
 
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applicable study-related facilities (e.g. research pharmacy, clinical laboratory, imaging 
facility, etc.).  
12.0 ETHICAL CONSIDERATIONS 
12.1 Research Ethics Board (REB) Approval 
Research Ethics Board (REB) approval will be obtained prior to beginning any research-
specific procedures. Following initial ethics approval, ongoing ethical approval will be 
maintained and the clinical trial will undergo REB review at least annually, in accordance 
with regulatory and REB requirements. The clinical trial will be conducted in accordance 
with the REB-approved study documents and the determinations (including any 
limitations) of the REB, and in compliance with REB requirements. Any amendments to 
the protocol will require review and approval by the REB before the changes are 
implemented in the clinical trial, unless to eliminate an immediate hazard to the 
participant. 
 
Whenever new information becomes available that may be relevant to participant 
consent, a consent form and/or consent for addendum will be presented to the REB for 
review and approval prior to its use. Any revised written information will receive REB 
approval prior to use. 
12.2 Informed Consent Process & Documentation 
Informed consent is a process that is initiated prior to the individual agreeing to take part 
in the clinical trial and continues throughout their participation. 
 
Informed consent will be obtained from each participant prior to their participation in the 
clinical trial. Informed consent will be obtained by appropriately trained and qualified 
CAMH research personnel who do not have an existing clinical relationship with the 
participant or caregiver The PI will not obtain participant consent. Informed consent will 
be obtained in-person.  
 
Each participant will be provided with a current copy of the REB approved ICF prior to the 
consent discussion. Research personnel will explain the clinical trial to the participant and 
answer any questions that may arise. This discussion will include an explanation of the 
clinical trial purpose, procedures, potential 
risks and benefits, confidentiality 
considerations and participant rights (e.g. participants will not be penalized or lose any 
benefits regardless of what they decide and they have the right to withdraw from the 
clinical trial at any time). Participants may take as much time as they need to make their 
decision, and may consult with others (e.g. family members, other health care providers, 
etc.) if they like. Following the consent discussion, and once the participant has decided 
to take part, the participant, and the person conducting the consent discussion will 
personally sign and date the ICF. Each participant will be provided with a complete (fully 
signed) copy of the ICF. The original ICF(s) and the informed consent process will be 
documented in the source documents. 
 

 
 
 
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Each study visit occurring onsite, including the consent visit, will follow the most current  
institutional IPAC guidelines put forth by CAMH to ensure staff and participants are 
protected against COVID-19 and other infectious diseases (e.g. participant screening 
upon entry, frequent hand-washing, masks for participants and staff).  
 
13.0 PRIVACY AND CONFIDENTIALITY 
 
All clinical trial-related documents and data will be held in strict confidence and stored at 
CAMH or on CAMH servers, and will follow CAMH policies and procedures to ensure 
participant privacy and confidentiality.  
 
All research activities will be conducted in as private a setting as possible. The study team 
(including the PI), the study monitor, representatives of the REB, and Health Canada may 
inspect all documents and records required to be maintained by the PI, including but not 
limited to, medical records and pharmacy records for the participants in this clinical trial. 
The participant’s contact information will be securely stored at CAMH for internal use 
during the clinical trial. At the end of the clinical trial, all records will continue to be kept in 
a secure location in accordance to applicable institutional and regulatory requirements. 
Safety reports on AEs and SAEs will be reported to Filament Health within 24hrs of the 
event occurring. In addition, safety data generated from the trial regarding the use of 
psilocybin and a report on the safety and efficacy of the clinical trial data will be provided 
to Filament Health Corp. None of these safety reports will contain PHI and all data will be 
coded.  
 
There is a potential risk of breach of confidentiality that is inherent in all research 
protocols. Breach of confidentiality will be minimized by the research staff who will 
maintain research data (identified only by participant code number not related to name, 
or date of birth). A list of participant names, their ID numbers, and information about how 
they can be reached will be kept in a separate locked cabinet with access only to study 
personnel authorized by the PI. To minimize the risk of breach of confidentiality formal 
training sessions for all research staff emphasizing the importance of confidentiality will 
be conducted and formal mechanisms limiting access to information that can link data to 
individual participants will be monitored and established by study personnel. All 
information obtained from participants will be kept as confidential as possible. Computer-
based files/data will be entered into password-secured databases (details below) and 
paper-based files will be stored in a secure location. These data will only be accessible 
to personnel involved in the study and they will abide by confidentiality regulations of the 
REB.  
 
In unusual cases, a participant’s research record may be released in response to a court 
order. If the research team learns that a participant or someone with whom the participant 
is involved with is in serious danger or harm, an investigator will inform the appropriate 
agencies. 
 

 
 
 
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Data from this study will be entered into a secure REDCap database.  At point-of-entry, 
data values will undergo consistency edits (e.g., ID validation, range verification, duplicate 
detection) and personnel will be required to correct errors. Reports will be created via the 
REDCap program. Data management staff will run logic error programs to check for 
accuracy and irregularities within and across data structures and within and across sites. 
Quality assurance checks will be conducted regularly by study personnel. Although 
unlikely, instances may occur where REDCap is not available.  In the case that this 
happens, we will follow the CAMH REDCap Downtime Procedures. 
 
Imaging Data 
Digital files of PET and MRI data will be considered source documents and will be stored on a 
password-locked computer without personal identifying information. The PSF will note the day 
and time of the PET scan, its number in the PET Centre Database, the injected radioactivity and 
a note to the effect that the scan was completed with no technical problems. 
 
A secure central registry at the CAMH PET centre tracks research participants who complete PET 
scans to ensure radiation exposure does not exceed the annual or lifetime limits set by the centre 
and by the Canadian Nuclear Safety Commission. This registry records participants’ name, date 
of birth, and participation in this and (if applicable) other studies. This information is maintained in 
a secure system not linked to other medical records and is accessible only by the PET Centre’s 
Nuclear Safety Officer. 
 
In accordance with Health Canada regulations for Basic Research Applications involving Positron-
Emitting Radiopharmaceuticals, all data and all appropriate documentation will be stored for 10 
years after the completion of the study, which meets the requirement for retention of study 
documents for at least 5 years after completion of the study. 
 
14.0 CLINICAL TRIAL FINANCES 
14.1 Funding Source 
This study is funded by the Centre for Complex Interventions and the CAMH Brain 
Health Imaging Centre at the Centre for Addiction and Mental Health (CAMH).  
14.2 Conflict of Interest 
The research team does not have any conflicts of interest to disclose.  
 
15.0 PUBLICATION POLICY/DATA SHARING 
In the publication of the results of research, the investigators are obliged to preserve the 
confidentiality of all research participants. Participants will not be identified in any 
publication of research results. The results of this study will be published as group data 
without the use of characteristics that would identify individual participants. The study 
investigator will hold the primary responsibility for the publication of the results of the 
clinical trial. All publications will follow CAMH policies associated with publications.  

 
 
 
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15.1 Future Secondary Use of Data 
 
De-identified data from this project may be used for future research by internal and/or 
external project collaborators in the future. The research team may share de-identified 
data with other researchers at CAMH or with collaborators around the world. Coded data 
that has been collected may also be combined with data collected from other people on 
other studies or it may be saved in a database. This is an optional part of the study for 
participants. On the ICF, participants can indicate whether they consent to allowing their 
data to be shared and/or pooled in the future.  
 
16.0 REFERENCES 
 
Broder, M. S., Bates, J. A., Jing, Y., Hebden, T., Forbes, R. A., & Chang, E. (2012). Association 
between second-generation antipsychotic medication half-life and hospitalization in the 
community 
treatment of adult 
schizophrenia. 
J Med Econ, 15(1), 105-111. 
https://doi.org/10.3111/13696998.2011.632042  
 
Buchborn, T., Schröder, H., Höllt, V., & Grecksch, G. (2014, Jun). Repeated lysergic acid 
diethylamide in an animal model of depression: Normalisation of learning behaviour and 
hippocampal 
serotonin 
5-HT2 signalling. 
J Psychopharmacol, 28(6), 545-552. 
https://doi.org/10.1177/0269881114531666  
 
Busner, J., & Targum, S. D. (2007, Jul). The clinical global impressions scale: applying a research 
tool in clinical practice. Psychiatry (Edgmont), 4(7), 28-37.  
 
Cameron, L. P., Benson, C. J., DeFelice, B. C., Fiehn, O., & Olson, D. E. (2019, Jul 17). Chronic, 
Intermittent Microdoses of the Psychedelic N,N-Dimethyltryptamine (DMT) Produce 
Positive Effects on Mood and Anxiety in Rodents. ACS Chem Neurosci, 10(7), 3261-3270. 
https://doi.org/10.1021/acschemneuro.8b00692  
 
Cameron, L. P., Benson, C. J., Dunlap, L. E., & Olson, D. E. (2018, Jul 18). Effects of N, N-
Dimethyltryptamine on Rat Behaviors Relevant to Anxiety and Depression. ACS Chem 
Neurosci, 9(7), 1582-1590. https://doi.org/10.1021/acschemneuro.8b00134  
 
Cantù, F., Ciappolino, V., Enrico, P., Moltrasio, C., Delvecchio, G., & Brambilla, P. (2021, Feb 
1). Augmentation with Atypical Antipsychotics for Treatment-Resistant Depression. J 
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