Clinical trial NCT04749745
Conditions: Cortical Excitability Psychiatric Disorder
Keywords: L-theanine Cortical Excitability NMDA GABA Paired-Pulse TMS
Sponsor: Butler Hospital
Start date: 2020-06-09; Completion date: 2021-05-31
Enrollment: 11 participants; Allocation: RANDOMIZED; Intervention model: CROSSOVER

Brief summary:
Major depressive disorder (MDD) is a serious mental illness and the leading cause of disability worldwide. New pharmacotherapeutic agents with complementary neurobiological mechanism and better side effect profile are of great needs. In addition to the monoamine system, the glutamatergic system plays a crucial role in MDD.

L-theanine (N5-ethyl-L-glutamine) is the primary psychoactive component uniquely in green tea. Preclinical studies have demonstrated anti-depressant effect of L-theanine in rodents and provided evidences for its pharmacological properties of N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA) agonism. Yet these effects have not been proven in humans. Only one open-label clinical trial has studied and supported antidepressant effects of L-theanine in MDD patients. We propose using pair-pulse transcranial magnetic stimulation (ppTMS) to probe how L-theanine may manipulate the glutamatergic and GABA systems in the frontal region by changing cortical excitability first in healthy subjects. We plan to investigate the neurobiological effects of L-theanine in healthy subjects first.

Granted that the first phase pilot trial provides neurophysiological evidence of L-theanine on motor cortex excitability in human subjects, next phases of studies on L-theanine in MDD patients cortical excitability could be justified.

Detailed description:
Background and Significance:

Major depressive disorder (MDD) is a serious mental illness and the leading cause of disability worldwide. Although many antidepressants acting on synaptic monoamine levels have been used as the first-line drug treatment for MDD, around one third of MDD are pharmacologically resistant. Side effects of these medications impose additional hardship on adherence and further affect treatment outcome. New pharmacotherapeutic agents with complementary neurobiological mechanism and better side effect profile are of great needs. In addition to the monoamine system, the glutamatergic system plays a crucial role in MDD.

L-theanine (N5-ethyl-L-glutamine) is the primary psychoactive component uniquely in green tea. Epidemiological studies support that green tea consumption is an independent factor associated with lower prevalence of depression. Preclinical studies have demonstrated anti- depressant effect of L-theanine in rodents and provided evidences for its pharmacological properties of N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA) agonism. Yet these effects have not been proven in humans. Only one open-label clinical trial has studied and supported antidepressant effects of L-theanine in MDD patients. We propose using pair-pulse transcranial magnetic stimulation (ppTMS) to probe how L-theanine may manipulate the glutamatergic and GABA systems in the frontal region by changing cortical excitability first in healthy subjects. ppTMS is a well-established technique to investigate frontal motor cortical excitability mediated by the inter-neuron NMDA and GABA receptors. Specific changes of ppTMS measures, including impaired short-term and long-term intracortical inhibition (SICI, mediated by GABA-A receptor; LICI, mediated by GABA-B receptor) and intracortical facilitation (ICF, mediated by NMDA receptor), have been demonstrated in MDD. Using this technique, we plan to investigate the neurobiological effects of L-theanine in healthy subjects first.

Granted that the first phase pilot trial provides neurophysiological evidence of L-theanine on motor cortex excitability in human subjects, next phases of studies on L-theanine in MDD patients cortical excitability could be justified. This will lay foundation for further exploration of L-theanine's potential as an augmenting agent for MDD in a placebo- controlled design.

Aims and Hypothesis:

Given the potential NMDA and GABA agonistic effects of L-theanine, we hypothesize that it increases intracortical inhibition and facilitation through enhancement of NMDA- and GABA-receptor mediated neurotransmission, in healthy subjects (N=10 to complete study).

Study Procedures:

Double-blinded, Randomized-order, Cross-over placebo-controlled to evaluate acute effect of single-dose L-theanine on motor cortex excitability by ppTMS in 10 healthy subjects.

Dose of L-theanine or placebo is 400mg. At baseline, subjects will be randomized to L- theanine or placebo group, then receive ppTMS protocol before drug administration. The ppTMS protocol is repeated after 30min of administration. Then subjects will return to clinic after 1 week free of any medications and repeat the above protocol with the second drug condition. Visual analog scale will be used to evaluate psychosomatic symptoms and wellbeing of the subjects pre- and post-each drug administration.

Data Analytic Plan:

Wilcoxon test will be used to compare the baseline-to-post-drug means of SICI, LICI and ICF measures. Prespecified covariates include age, sex, handedness, level of fatigue will be analyzed in linear regression model. The time-condition relationship with continuous dependent variables of ICI and ICF values will be evaluated by Mixed Effect Model. Two- sided P value \< 0.05 is considered statistically significant.

Arms: arm 1: Subject will receive 400mg single dose of L-theanine, by oral ingestion with water. The capsules are prepared and dispensed by hospital pharmacy, with the investigator and participant both blinded. arm 2: Subject will receive 400mg single dose of matching Placebo, by oral ingestion with water. The capsules are prepared and dispensed by hospital pharmacy, with the investigator and participant both blinded.
Interventions: intervention 1: L-theanine intervention 2: Placebo
Intervention descriptions: intervention 1: The subject will receive paired-pulse TMS (ppTMS) procedure before and 30min after taking the drug orally, to assess motor cortex excitability, measured by surface electromyogram (EMG). The ppTMS procedure is administered by a TMS stimulator controlled a program software named Signal. The coil of the stimulator is placed above the scalp where the stimulation would activate the left primary motor cortex region that controls the right thumb. When a pulse stimulation is delivered by the coil, the EMG over a thumb muscle (abductor pollicis brevis) will record a motor-evoked potential on the tracing. Cross-over with placebo in two separate sessions at least 72 hours apart. intervention 2: The subject will receive paired-pulse TMS (ppTMS) procedure before and 30min after taking the drug orally, to assess motor cortex excitability, measured by surface electromyogram (EMG). The ppTMS procedure is administered by a TMS stimulator controlled a program software named Signal. The coil of the stimulator is placed above the scalp where the stimulation would activate the left primary motor cortex region that controls the right thumb. When a pulse stimulation is delivered by the coil, the EMG over a thumb muscle (abductor pollicis brevis) will record a motor-evoked potential on the tracing. Cross-over with L-theanine in two separate sessions at least 72 hours apart.

Protocol documents:
Prot_SAP_000.pdf: 
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Local IRB # 202006-003   IRBNet # 1599521 
BUTLER HOSPITAL 
INSTITUTIONAL REVIEW BOARD 
PROTOCOL 
1.) Project  
Title of Project: Effects of L-theanine on Motor Cortex Excitability in Healthy Subjects: A Paired-Pulse TMS 
Study 
Principal Investigator (PI):  Linda L. Carpenter, M.D. 
 
 
 
 
 
 
 
 
 
 
 
 
Other Investigator(s):  Shiwen Yuan, M.D. 
 
 
 
   
                  
2.) Description of Study 
A.  Specific Aims   
To study the effects of a single dose of L-theanine (L-γ-glutamylethylamide or N5-ethyl-L-glutamine) on motor 
cortex excitability in healthy subjects, using paired-pulse transcranial magnetic stimulation (ppTMS) measures. 
The hypothesis is that L-theanine enhances motor cortex excitability in healthy subjects.  
 
B.  Background  
L-theanine is the primary psychoactive component uniquely in green tea1. Epidemiological studies support that 
green tea consumption is an independent factor associated with lower prevalence of depression2-4. Preclinical 
studies have demonstrated anti-depressant effect of L-theanine in rodents and provided evidences for its 
pharmacological properties of N-methyl-D-aspartate (NMDA) and gamma-aminobutyric acid (GABA) agonism5-
7. Yet these effects have not been proven in humans. Only one open-label clinical trial8 has studied 
antidepressant effect of L-theanine in major depressive disorder, and suggested its effectiveness as an 
augmenting agent to an existing antidepressant regimen. Furthermore, the psychotropic properties and 
mechanism of L-theanine are to be elucidated. Paired-pulse transcranial magnetic stimulation (ppTMS) is a 
well-established technique to investigate frontal cortical excitability mediated by the inter-neuron NMDA and 
GABA receptors9. Several studies10-14 in subjects with MDD have demonstrated specific changes of ppTMS 
measures, including impaired short-term intracortical inhibition (SICI, mediated by GABA-A receptor and fast 
inhibitory postsynaptic potentials) and long-term intracortical inhibition (LICI, mediated by GABA-B receptor 
and slow inhibitory postsynaptic potentials) and intracortical facilitation (ICF, mediated by NMDA receptor and 
excitatory postsynaptic potentials), compared to healthy subjects. Treatment effects of MDD elicited by 
escitalopram corresponded with changes in these markers13. This is relevant to the study aim in that the motor 
cortex excitability is mediated by the glutamatergic system, and ppTMS offers an opportunity to investigate 
how L-theanine may manipulate the glutamatergic system in the frontal region by changing motor cortex 
excitability first in healthy subjects (phase 1, as described in this protocol). Then we plan to examine its 
potential as an augmenting agent for MDD in a placebo-controlled design (phase 2). 
 
C.  Experimental Method 
 
C1.  Brief Description of Subjects 
Adults (N=10 completing all 3 visits) (>18 and <65 years old) without any neuropsychiatric disorders or 
contraindication to application of TMS will be recruited from the local community. 
 
C2.  Study Design 
This is a double-blinded randomized order, cross-over, placebo-controlled trial to study the acute effects of a 
single dose of L-theanine on the motor cortex excitability, measured by paired-pulse TMS metrics.  
1) Visit 1: The subject will sign consent form to enter the study; A clinical interview (SCID 5, for 30- 
45min) will be conducted by a SCID interview-trained clinician (Shiwen Yuan) to ensure the inclusion and 
exclusion criteria are met. Releases will be signed to obtain records that confirm eligibility from a 
medical standpoint.  


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Eligible subject will then be instructed to refrain from any nutraceuticals or psychotropic  
medications for 7 days prior to visit 2. After medical clearance, the subject will be randomized to active  
or placebo pill. 
2)  On visit 2: the subject will receive the first session of ppTMS data collection procedures (see below for 
details). During this session measurement of cortical excitability happens before and after ingestion of 
a capsule (active L-theanine or placebo). The subject will be instructed to continue to refrain from any 
nutraceuticals or psychotropic medications until visit 3, which is scheduled within one week. 
3)  On visit 3: The subject will receive ppTMS data collection procedures that are identical to visit 2, before 
and 30min after drug administration. If the subject was given active L-theanine during visit 2, they will 
receive placebo during visit 3; if the subject was given placebo during visit 2, they will receive active L-
theanine during visit 3. The PI and co-PI will still be blinded regarding the condition of the drug. 
Arrangements will be made for compensation and participation will conclude. 
 
C3.  Specific Procedures or Treatments 
At both visits 2 and 3, all subjects will undergo a standard ppTMS protocol once before and again after 
administration of a single dose of active L-theanine or placebo. This protocol involves delivery of programed 
ppTMS stimuli (magnetic pulses) to the head over the motor cortex while measuring the resulting evoked 
motor potentials through surface electromyography (EMG) on the subject’s hand. 
 
MOTOR THRESHOLD DETERMINATION: EMG will be recorded from the right abductor pollicus brevis (APB; 
thumb) muscle in order to measure the amplitude of motor evoked potentials (EMG) recorded by LabChart 
software throughout the procedure. The subject will be seated comfortably, given earplugs, and instructed to 
maintain relaxed throughout the experiment. Sticky electrodes will be attached to the skin around the thumb 
and wrist of the subject’s right hand.  Single pulses of TMS will be applied to the area of the left motor cortex 
corresponding with right thumb muscle ABP (using with a Magstim figure-of-eight magnetic coil and Magstim 
stimulators) to determine the resting motor threshold (RMT), defined as the intensity that produces a MEP in 
relaxed APB muscle of > 50 uV during 5 of 10 trials. This value is used to calibrate the intensity of pulses for the 
ppTMS measures of cortical excitability. 
 
PAIRED-PULSE TMS PROTOCOL: Paired pulses of TMS will subsequently be used to assess various measures of 
cortical excitability. For example, for intercortical facilitation (ICF) measurement, a subthreshold conditioning 
stimulus (CS) at 80% RMT precedes a suprathreshold testing stimulus (TS) at 120%RMT.  Inter-stimulus 
intervals (ISIs) of different durations, e.g., 10 ms and 20 ms will be used. ICI will be tested with a 
suprathreshold CS at 120% of RMT followed by test stimulus at 120% of RMT. Again, trials will be repeated 
with at ISIs of different durations, e.g. 2, 5, 50, and 100ms.  
 
Each ppTMS protocol will consist of 25 trials for each of the six conditioned stimuli in random order. MEP 
amplitudes will be recorded from each trial. SICI, ICF and LICI metrics are estimated from averages of the 
conditioned MEP amplitudes.  
 
DRUG ADMINISTRATION:  The subject will be dispensed a single dose of either drug or placebo as prepared by 
an unblinded pharmacist. The subject will take placebo or L-theanine 400mg of with water and remain sitting 
in a quiet room for relaxation for 30min, after which the ppTMS protocol will be repeated. The PI/co-PI and the 
subject will be blinded to the result of randomization.  
 
SAFETY ASSESSMENTS: Prior to starting TMS procedures, the subject will be screened for TMS risk with a 
standard TMS Safety Screen questionnaire. Visual analog scales (e.g. sense of calm, anxiety level, sedation, 
irritability, level of fatigue), will be completed prior to and following each ppTMS protocol to evaluate effects 
of the stimulation as well as possible effects of L-theanine on mood. Verbal query will be used to elicit any 
other adverse effects. Subjects will be discharged from the research facility after each visit when it is clear they 


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are comfortable and suitable to drive home. The total estimated time for each visit is estimated to be 2.5 hours 
to 3 hours.  
 
C4.  Data Analysis  
No previous studies have been done on the effects of L-theanine on intracortical facilitation or inhibition. 
However, many similar studies have been done with ppTMS to evaluate pharmacological effects of a drug on 
these same cortical excitability measures. Previous studies on the effects of NMDA receptor antagonists 
(dextromethorphan15, memantine16) on ICF and of GABA receptor agonist (benzodiazepine17) on ICI. Those 
studies had sample sizes that ranged from 8-10 healthy individuals. The estimated clinically meaningful effect 
size is 10% of change in the ICI and/or ICF. Thus, after consultation with Rich Jones, PhD on sample size 
estimation, we plan to collect a full set of data from N=10 healthy subjects. The Pharmacy Department will 
participate in the process of L-theanine/placebo packing, storage, randomization and distribution.  
 
SICI, ICF and LICI values were calculated by the ratio of conditioned MEP / unconditioned MEP. We used 
Wilcoxon signed-rank tests to compare the baseline-to-post-drug changes (D=post-drug value minus pre-drug 
value) of SICI, ICF and LICI between placebo and L-theanine conditions. Two-sided P value < 0.05 is considered 
statistically significant.   
 
D.  Material Inducements 
Subjects will be compensated in the form of gift cards for their participation: 
$20 for participating in informed consent and initial SCID-5 interview; 
$50 for participating in the first session of placebo/L-theanine administration and ppTMS procedures; 
$80 for participating in the second/last session of placebo/L-theanine administration and ppTMS procedures. 
Therefore, Subjects will be compensated in the form of gift cards for their participation as follows: $20 for 
completion of visit 1; $50 for completion of visit 2; and $80 for completion of visit 3. They will be compensated 
$150 in total if they completed the whole study. 
 
E.   Training of Research Personnel 
The PI and co-principal investigator (Shiwen Yuan) have received SCID-5 training for clinical interview and will 
have TMS research credentials completed/documented by the Butler Neuromodulation Research Facility, per 
policy. The PIs have received CITI training program for conflict of interest in human subject research and good 
clinical practice, REDCap programming training for data management. A special ppTMS workshop with Pete 
Fried, PhD from BIDMC is planned for technical training on the ppTMS protocol.   
 
3)  Human Subjects 
A.  Subject Population  
We plan to enroll enough subjects to ensure N=10 subjects who meet inclusion criteria complete all 3 visits: 
1) Adult, aged between 18 and 65 years old; 
2) Able to read/speak English and give informed consent 
3) No current or history of Axis I psychiatric disorders by DSM-5. 
4) Free of psychotropic medication use 
Exclusion Criteria: 
1) History of significant acute or chronic neurological or medical disorder or condition that increases risk 
for seizure with TMS; 
2) History of alcohol use disorder, nicotine dependence, adjustment disorder; 
3) History of allergic reactions to L-theanine or green tea; 
4) Pregnancy; 
5) Unable/unwilling to abstain from nutraceutical supplements and psychotropic agents during 
participation in the study 


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6) Unable/ unwillingness to refrain from recreational substance use (e.g. alcohol or marijuana) during 
participation in the study;  
7) Meet criteria for exclusion from TMS or MRI procedures, including intracranial metal implants or 
nonremovable ferromagnetic items in the head/neck. 
 
B.  Recruitment and Consent Procedures  
Subjects will be recruited through media advertisement, including social media, flyers. Potential sources of 
subjects include the community, hospitals, schools, etc. Telephone screening will be used to explain the study 
and establish preliminary eligibility for those who express interest. Written informed consent will be obtained 
at the first visit, after describing the study in detail and answering all questions; if COVID-19 pandemic 
precautions preclude in-person evaluation, virtual screening and consent procedures will take place. 
 
Given continued COVID-19 pandemic situation, we will implement video and phone session for the first visit. A 
“VERBAL CONSENT FOR USE OF E-MAIL AND VIDEOCONFERENCING IN A RESEARCH PROJECT”  will be used. In 
this consent process, prospective subjects will be contacted by phone and informed of the consent proposal. 
They will be asked if they understand and agree to videoconferencing for evaluation and email communication 
for scheduling purposes.  They will need to confirm if they have access to a computer, tablet, or smartphone 
with a built-in camera. The investigators will then follow the scripts described in the consent form word by 
word to the subjects. Risks (including confidentiality) and benefits (including reduced risk of exposure to 
COVID-19) will be reviewed.  
At the end of the consent form, the investigator will sign and date to indicate that all the instructions have 
been followed and the subject gave informed consent.  
 
 
C.  Potential Risks   
 
1. We acknowledge the risk of loss of confidentiality in the course of the study.  
 
2. Potential risks from L-theanine administration 
L-theanine is a generally safe nutraceutical agent. There are two clinical trials that studied patients with MDD8 
(N=20) or schizophrenia/schizoaffective disorders18(N=52), and reported minimal side effects from 250mg-
400mg daily dosing for 8 weeks. Hidese et al8 reported “1 patient reported slight sleepiness; 2 patients 
reported increased duration of sleep of up to 2 hours than usual; 2 patients reported increased dream activity. 
All tolerated the medication without drop-out”. Ritsner et al18 reported “L-theanine did not produce any side 
effects”. Studies29, 30 that administered a single dose of 250mg L-theanine before evaluating task 
electroencephalography (EEG) in healthy human subjects (N=13-15) reported no side effects. L-theanine was 
still tolerated well after two weeks of supplementing with doses nearly 60 times the usual amount used in 
animal studies.19,20 Therefore, we anticipate minimal if any side effects from 400mg one-time dosing of L-
theanine, as proposed in this study. Potential risks are limited to allergic reaction (extremely rare) and 
sleepiness/increased length of sleep or increased dream activity (rare). 
 
3. Potential risks from ppTMS procedure  
Headache (5%-10%)21, Scalp discomfort (5%-30%)22, dizziness or fainting episode, seizure, with an estimated 
risk of 0.003%23 are the potential risks of high-frequency repetitive TMS delivered to the dorsolateral 
prefrontal cortex as a treatment modality. ppTMS (2 pulses each time) delivers a significantly lower amount of 
energy, which reduces the potential risks, but the ppTMS protocol pulses are delivered over the motor cortex, 
which could increase risk of seizure induction if given in high frequency trains. The ppTMS procedure does not 
delivery high frequency pulses and thus carries the same risks associated with a standard motor threshold 
procedure, which include scalp discomfort, hearing acuity damage, seizure. Single or paired-pulse TMS has an 
estimated risk of 2/100,000 of inducing seizure in low-risk healthy subjects (Rossi 2020, review manuscript).  


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D.  Protection of the Subject  
 
 
D1. Measures to Minimize Potential Risks 
1. Minimize risks of loss of confidentiality: see D2.  
2. Minimize potential risks from L-theanine: 
1) Clinical interview on visit 1 to ensure inclusion and exclusion criteria. Prevent subjects from 
exposure to L-theanine if there is a history of known allergic reaction. 
2) Observation for 1 hours after the administration of L-theanine (during ppTMS procedure and 
safety assessment after the procedure), to ensure that the subject has no sedation or other side 
effects. 
3. Minimize potential risks from ppTMS procedure: 
1) Clinical interview at visit 1 to ensure inclusion and exclusion criteria.  
2) Medical clearance procedure and screening with TMS safety screen tools to prevent subjects from 
exposure to TMS if there is any increased risk of seizure.  
3) Comfortable positioning, ongoing direct monitoring of subject for adverse effects 
4) All TMS procedures will be conducted by PI/co-PI who are medical doctors and TMS-trained 
5) Ear plugs will be provided to subjects to prevent hearing damage. 
6) All procedures to be conducted in the BNRF, a specialized neuromodulation research facility at 
Butler with all-day coverage by TMS-trained physicians, emergency response buttons/protocols, 
etc. Subjects will also be monitored closely for dizziness, fainting or syncopal episode, and 
differentiate from seizure. Staff receive training in detection and management of seizure and 
syncope during neuromodulation procedures. 
 
D2. Measures to Ensure Confidentiality 
1. The clinical interview and medical clearance documents will be stored in a locked cabinet within the 
Butler Neuromodulation Research Facility (BNRF) facility, which is locked after hours and has limited 
keyed access for a small number of BNRF research staff.  
2. All subjects will be assigned a study ID number upon enrollment and ID will be used for research data 
capture. 
3. This study will use Care New England’s instance of REDCap for the collection and storage of data. 
REDCap is a secure, web-based application developed by Vanderbilt University for building and 
managing surveys and databases. It is primarily designed to support online or offline data capture for 
research studies, quality improvement, and operations. Care New England’s instance of REDCap is 
hosted within the Care New England data center in Warwick, RI. This REDCap instance is role-based 
and is fully integrated with CNE’s Active Directory structure. It enjoys 24/7/365 enterprise-level 
support and security inherit to CNE’s HIPAA-compliant data center. Network transmissions (data entry, 
survey submission, and web browsing) to and from REDCap are protected via TLS 1.2 encryption.  
REDCap’s data is stored on encrypted servers within CNE’s data center. 
 
D3. Data Safety Monitoring Plan 
We plan to establish a data monitoring panel with the PI (Carpenter) and co-PI (Yuan), and several unaffiliated 
clinical researchers with relevant expertise. The group will review the study and its progress prior to initiation.   
The PI/co-PI will present all adverse effect data to the panel and report any other issues related to safety. 
Weekly meetings between Dr. Carpenter, Dr. Yuan (and any BNRF staff involved in the project) will be held to 
review progress and adverse events. 
 
We plan to do an interim analysis as mentioned above to re-estimate sample size, when N=5 subjects have 
been enrolled.  In cases of any adverse effects from TMS or L-theanine, a comprehensive evaluation of the 
severity of the effect (and reported to the Butler IRB if determined a reportable event per IRB guidelines) and if 


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the subjects wish to stay in the study they will be aware they have the opportunity to withdraw at any time of 
the study. When statistically significant differences are observed for the ppTMS measures (SICI, LICI, ICF) in a 
dose-dependent correlation with L-theanine, or there are no differences observed whatsoever, the study will 
be concluded.   
 
E.  Potential Benefits  
The study will contribute valuable data to elucidate the effects of L-theanine on motor cortex excitability. If the 
study yields positive results, it could support a phase 2 study on the effects of L-theanine on motor cortex 
excitability in patients with MDD and establish the foundation of L-theanine as a potential augmenting agent 
for pharmacotherapy of MDD.  
 
F.  Risk-Benefit Ratio  
The risk-benefit ratio is estimated to be minimal considering the significant benefit that could be potentially 
generated from the study, versus the very low risks of the two procedures as mentioned above, as well as the 
measures that will be taken to further minimize those risks.  
4) REFERENCES  
1. Vuong QV, Bowyer MC, Roach PD. L-Theanine: properties, synthesis and isolation from tea. J Sci Food Agric. 2011;91(11):1931-9. 
2. Kim J, Kim J. Green Tea, Coffee, and Caffeine Consumption Are Inversely Associated with Self-Report Lifetime Depression in the 
Korean Population. Nutrients. 2018;10(9). 
3. Hintikka J, Tolmunen T, Honkalampi K, et al. Daily tea drinking is associated with a low level of depressive symptoms in the 
Finnish general population. Eur J Epidemiol. 2005;20:359-363.  
4.  Hozawa A, Kuriyama S, Nakaya N, et al. Green tea consumption is associated with lower psychological distress in a general 
population: The Ohsaki Cohort 2006 Study. Am J Clin Nutr. 2009;90:1390-1396.  
5. Wakabayashi C, Numakawa T, Ninomiya M, et al. Behavioral and molecular evidence for psychotropic effects in L-theanine. 
Psychopharmacology 2012;219:1099–1109. 
6. Egashira N, Ishigami N, Pu F, et al. Theanine prevents memory impairment induced by repeated cerebral ischemia in rats. 
Phytother Res. 2008;22(1):65-8. 
7. Lardner AL. Neurobiological effects of the green tea constituent theanine and its potential role in the treatment of psychiatric 
and neurodegenerative disorders. Nutr Neurosci. 2014;17(4):145-55. 
8. Hidese S, Ota M, Wakabayashi C, et al. Effects of chronic L-theanine administration in patients with major depressive disorder: 
an open-label study. Acta Neuropsychiatr. 2017;29(2):72-79. 
9. Paulus W, Classen J, Cohen LG, et al. State of the art: Pharmacologic effects on cortical excitability measures tested by 
transcranial magnetic stimulation. Brain Stimul. 2008;1(3):151-63. 
10. Radhu N, de Jesus DR, Ravindran LN, et al. A meta-analysis of cortical inhibition and excitability using transcranial magnetic 
stimulation in psychiatric disorders. Clin Neurophysiol. 2013;124(7):1309-20. 
11. Bajbouj M, Lisanby SH, Lang UE, et al. Evidence for impaired cortical inhibition in patients with unipolar major depression. Biol 
Psychiatry. 2006;59(5):395-400. 
12. Lefaucheur JP, Lucas B, Andraud F, et al. Inter-hemispheric asymmetry of motor corticospinal excitability in major depression 
studied by transcranial magnetic stimulation. J Psychiatr Res. 2008;42(5):389-98. 
13. Levinson AJ, Fitzgerald PB, Favalli G, et al. Evidence of Cortical Inhibitory Deficits in Major Depressive Disorder. Biol Psychiatry. 
2010;67(5):458-64. 
14.  Jeng JS, Li CT, Lin HC, et al. Antidepressant-resistant depression is characterized by reduced short- and long- interval cortical 
inhibition. Psychol Med. 2019;3:1-7. 
15. Ziemann U, Chen R, Cohen LG, Hallett M. Dextromethorphan decreases the excitability of the human motor cortex. Neurology 
1998;51:1320-1324. 
16. Schwenkreis P, Witscher K, Janssen F, et al. Influence of the N-methyl-D-aspartate antagonist memantine on human motor 
cortex excitability. Neurosci Lett 1999;270:137-140. 
17. Di Lazzaro V, Oliviero A, Saturno E, et al. Effects of lorazepam on short latency afferent inhibition and short latency intracortical 
inhibition in humans. J Physiol 2005;564(2):661-668. 
18. Ritsner MS, Miodownik C, Ratner Y, et al. L-theanine relieves positive, activation, and anxiety symptoms in patients with 
schizophrenia and schizoaffective disorder: an 8-week, randomized, double-blind, placebo-controlled, 2-center study. J Clin 
Psychiatry. 2011 Jan;72(1):34-42. 


IRB v. 2019.07.18 
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Protocol Version (4) 
 
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19. Rao T, Ozeki M, Juneja LR. Suntheanine: A pure and safe L-theanine dietary supplement for relaxation and stress relief. Nutracos 
2007; 26-30. 
20. Borzelleca JF, Peters D, Hall W. A 13-week dietary toxicity and toxicokinetic study with l-theanine in rats. Food Chem Toxicol. 
2006;44(7):1158-66. 
21. Taylor JJ, Borckardt JJ, George MS. Endogenous opioids mediate left dorsolateral prefrontal cortex rTMS-induced analgesia. 
Pain. 2012;153(6):1219-25. 
22. Health Quality O. Repetitive Transcranial Magnetic Stimulation for Treatment-Resistant Depression: A Systematic Review and 
Meta-Analysis of Randomized Controlled Trials. Ont Health Technol Assess Ser. 2016;16(5):1-66. 
23. Carpenter LL, Janicak PG, Aaronson ST, Boyadjis T, Brock DG, Cook IA, et al. Transcranial magnetic stimulation (TMS) for major 
depression: a multisite, naturalistic, observational study of acute treatment outcomes in clinical practice. Depress Anxiety. 
2012;29(7):587-96. 
24. Levkovitz Y, Isserles M, Padberg F, Lisanby SH, Bystritsky A, Xia G, et al. Efficacy and safety of deep transcranial magnetic 
stimulation for major depression: a prospective multicenter randomized controlled trial. World Psychiatry. 2015;14(1):64-73. 
25. Rossi S, Hallett M, Rossini PM, Pascual-Leone A. Safety, ethical considerations, and application guidelines for the use of 
transcranial magnetic stimulation in clinical practice and research. Clinical neurophysiology: official journal of the International 
Federation of Clinical Neurophysiology. 2009;120(12):2008-39. 
26. AH C. Guidance for Industry and Food and Drug Administrative Staff: Class II Special Controls Guidance Document: Repetitive 
Transcranial Magnetic Stimulation (rTMS) Systems. US Department of Health and Human Services, Food and Drug Administration. 
2011. 
27. McClintock SM, Reti IM, Carpenter LL, McDonald WM, Dubin M, Taylor SF, et al. Consensus Recommendations for the Clinical 
Application of Repetitive Transcranial Magnetic Stimulation (rTMS) in the Treatment of Depression. J Clin Psychiatry. 2018;79(1). 
28. Wassermann EM. Risk and safety of repetitive transcranial magnetic stimulation: report and suggested guidelines from the 
International Workshop on the Safety of Repetitive Transcranial Magnetic Stimulation, June 5-7, 1996. Electroencephalogr Clin 
Neurophysiol. 1998;108(1):1-16. 
29. Gomez-Ramirez M, Kelly SP, Montesi JL, Foxe JJ. The Effects of L-theanine on Alpha-Band Oscillatory Brain Activity During a 
Visuo-Spatial Attention Task. Brain Topogr (2009) 22:44–51. 
30. Gomez-Ramirez M, Higgins BA, Rycroft JA, et al. The Deployment of Intersensory Selective Attention: A High-density Electrical 
Mapping Study of the Effects of Theanine. Clin Neuropharmacol 2007;30:25-38. 
5) CRITERIA FOR WAIVER OF AUTHORIZATION FOR USE OF PROTECTED HEALTH INFORMATION (PHI) 
5A. Does the requested use of PHI involve more than minimal risk to privacy? 
  YES [if " YES," project is not eligible for PHI Waiver]    
 NO [if "NO," address 1-3 below] 
 
1. Plan to Protect Patient Identifiers from Improper Use and Disclosure:  The clinical interview and medical 
clearance documents will be stored in a locked cabinet within the BNRF facility, which is locked after hours 
and has limited keyed access for a small number of BNRF research staff. All subjects will be assigned a 
study ID number upon enrollment and ID will be used for research data capture. All data will be de-
identified during analysis.  
 
2. Plan to Destroy Identifiers or Justification for Retaining Identifiers: The investigators plan to destroy 
identifiers once the data that need to be collected using the identifiers (including obtaining medical 
clearance documents from PCP) are obtained, by assigning study ID upon enrollment, shredding 
identifiable paper documents, etc. 
 
3. Assurances that the PHI will not be Re-used or Disclosed: The investigators assure that the PHI will not be 
reused or disclosed.  
 
5B. Could the research be practicably conducted without a waiver?  
 YES    
 NO 
5C. Could the research be practicably conducted without access to and use of the PHI?  
 YES    
 NO 
5D. PHI is only needed for activities preparatory to research  
YES    
 NO 
 


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6) DESCRIPTION OF PHI TO BE COLLECTED UNDER WAIVER  
Name, age, sex, handedness, contact information, medical history, substance and nutraceutical use history. (Medical 
clearance documents to be requested from PCP will be obtained following signature on a separate CNE Authorization 
form)   
 
7) ADVERTISEMENTS 
The advertisement will be submitted as amendment if the protocol is approved.  
 
8) RESRULTS INFORMATION 
Primary results: 
Compared to matching placebo, 400 mg single dose L-theanine elicited significantly higher post-pre drug change (D) of 
ICF (Mean±SE DICFL-theanine=0.073±0.073 vs. DICFPlacebo=-0.341±0.176, p=0.016, Cohen’s d = 1.02) and LICI (Mean±SE 
DLICIL-theanine=0.145±0.100 vs. DLICIPlacebo=-0.068±0.053, p=0.037, Cohen’s d = 0.91) within each individual. No significant 
difference was found for SICI (DSICIPlacebo= 0.005±0.060 vs. DSICIL-theanine=0.059±0.028, p=0.450, Cohen’s d = 0.35). L-
theanine did not change unconditioned MEPs (or baseline rMT) differently than placebo (Table 1). No adverse effects 
from L-theanine were observed. The subjects were unable to guess the condition of drug (placebo vs L-theanine) after 
each session of experiment more accurately than random. (SE = standard error of the mean) 
 

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  BUTLER HOSPITAL CONSENT FOR PARTICIPATION IN A RESEARCH PROJECT  
 
Effects of L-theanine on Motor Cortex Excitability in Healthy Subjects:  
A Paired-Pulse TMS Study 
 
Sponsorship 
This study is being paid for by internal funds at Butler Hospital. 
 
Research Project Summary 
L-theanine, a green tea extract, is an over-the counter “nutritional supplement” that has been shown to 
have anti-anxiety, anti-depression effects. This study aims to understand the effects of L-theanine on the 
brain, by testing how a single dose of L-theanine impacts excitability of neurons (nerve cells) in the brain. 
You are invited to participate in this study because you are a healthy adult and not taking medications 
that impact brain excitability. This study will require you to complete 3 visits in a research clinic at Butler 
Hospital over a period of 2-3 weeks. Being in the study will take you about 7 hours (1-3 hours per visit) in 
total. You will have an interview with one of our research staff to confirm your healthy status, and then 
attend two visits, each of which involves taking one dose of either L-theanine or placebo (sugar pill). Your 
brain excitability will be measured with a procedure called “paired-pulse transcranial magnetic 
stimulation (ppTMS)” and we will tell you more information about this below. You will be paid for 
participation in the study. This green tea extract is very safe and it has few bad effects after taking one 
dose. The main side effects from the TMS procedure include discomfort from sitting a prolonged period, 
and discomfort from the sensation of magnetic pulses on your head. There is also an extremely small 
chance of seizure and it will be discussed below.  
 
In order to decide whether or not you wish to be a part of this research study, you should know enough 
about its risks and benefits to make an informed judgment.  This consent form gives you detailed 
information about the research study which a member of the research team will discuss with you.  This 
discussion should go over all aspects of this research:  its purpose, the procedures that will be performed, 
risks associated with the procedures, possible benefits of participation, and possible alternatives.  Once 
you understand the study, you will be asked if you wish to participate; if so, you will be asked to sign this 
form.  This consent may contain words that you do not understand.  Please ask the investigator or the 
study staff to explain any words or information that you do not clearly understand. 
 
Description of Procedures 
If you decide to participate, you will have 3 visits to Butler Hospital: 
 
The first visit: You will have a talking session with the researcher to discuss this consent and to review 
your health history, to see if you qualify to participate in the study. You will be asked to provide a consent 
for us to contact your primary care physician to ensure you are free of any conditions that may prevent 
you from participating in the study.  
 
The second visit:  
1) You will participate in a procedure called “paired-pulse transcranial magnetic stimulation 
(ppTMS)”, which is a pulse of energy delivered by a piece of magnet over the scalp. It sends 
stimulation to the brain area that controls your hand movement. In the meantime, your right-hand 
muscle movement (electromyography, EMG) will be recorded by 2 stickers with small pieces of 
metal on them. This procedure will take about 30-45 minutes; You will need to not eat or drink 
during the experiment but can drink water.  
2) Then you will be given a capsule of either 400mg L-theanine (a green tea extract) or 400mg 
placebo (lactose), followed by 30 minutes of relaxation time sitting in a quiet room; You will not 


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know which (L-theanine or placebo) you received, to ensure a fair result. You will be able to 
stretch and walk around for a short period of time if you wish after taking the capsule.  
3) Then the ppTMS procedure in 1) will be repeated, which will take another 30-45 minutes. There 
will be assessments of safety before/during/after each ppTMS procedure. 
 
The third visit:  
1) Just like the second visit, you will first have the ppTMS procedure, which will take about 30-45 
minutes; You will need to not eat or drink during the experiment but can drink water.  
2) Then you will be given a capsule of what you did not receive in the second visit. In other words, if 
you received L-theanine in the second visit, you will get placebo this time; or if you received 
placebo in the second visit, you will get L-theanine this time. But you still will not know which (L-
theanine or placebo) you received, to ensure a fair result. This is again followed by 30 minutes of 
relaxation time sitting in a quiet room; You will be able to stretch and walk around for a short 
period of time if you wish after taking the capsule.  
3) Then the ppTMS procedure in 1) will be repeated, which will take another 30-45 minutes. There 
will be assessments of safety before/during/after each ppTMS procedure. 
 
 
 
Risks and Inconveniences 
 
Risks of ppTMS procedure include:  
1) 
Mild headache or scalp discomfort (5%-10%), usually mild if it happens and it typically gets better 
when you get used to the feeling of stimulation.  
2) 
Seizure, very rare, with an estimated risk of 2-3 in 100,000. You will be carefully screened for any  
risks of seizure before the study and closely monitored during the procedure.  
3) 
Dizziness or fainting. Usually due to anxiety about the procedure or dehydration. You will be 
closely monitored during the procedure. 
4) 
Hearing damage. This would not likely occur if you wear ear plugs that we provide to you  
during the procedure.  
 
Risks of taking L-theanine include: 
    1)  
Allergic reaction, extremely rare. 
    2)  
Sleepiness, increased length of sleep or increased dream activity, rare. 
3)  
The agent is given by mouth, hence an extremely rare risk of choking on the capsule. 
 
Risks of the placebo (because it will be lactose) include: 
1)    Allergic reaction, extremely rare. 
2)    Lactose intolerance. Please let the staff know if you have ever had diarrhea, gas or stomach upset 
after you drink milk.  
3)    The placebo is also given by mouth, hence an extremely rare risk of choking on the capsule. 
 
There is a risk of loss of confidentiality. However, the study team will have procedures to protect your 
privacy and identity, by assigning you a study ID, and destroying all information that could be use to 
identify you personally once the study is completed. 
 
Potential inconveniences include: 
The study will take about 7 hours in total of your time, divided into 2-3 visits (1-3 hours each visit). 
During the second and third visit, you will sit with your head still in a chair for most of the 3 hours; you 
may become tired or uncomfortable, but we will give you time to stretch.  You will need to travel to Butler 
Hospital for each visit, and we are not able to pay you for travel expenses but there is free parking on the 
hospital campus. You will also be asked to stop taking any caffeinated food/drink, stop using marijuana, 


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tobacco or any other drugs and over-the-counter supplements for 7 days before you receive the TMS 
procedures.   
 
Any medical treatment or procedure may have unforeseen side effects.  You should know that the 
prediction of effects from a treatment or procedure for any individual cannot be done with certainty, and 
unexpected potentially harmful effects occasionally occur with the administration of any type of 
treatment.  If you have questions about investigational procedures or treatments, or if you have any 
disturbing side effects during participation in this study, please tell our staff.   In the event of any 
unexpected, potentially harmful effects of any treatment or procedure given in this study, we will monitor 
your condition closely and institute appropriate treatment. If significant new knowledge is obtained 
through the course of the research which may change your mind about whether you would like to 
continue being in part of this study, you will be informed of this knowledge. 
 
Women Please Note:   
ppTMS procedure may be harmful to a growing fetus.  Therefore, you may be tested for pregnancy at the 
time of your admission to the study.  Prior to your beginning the study we will discuss with you in more 
detail the importance of avoiding pregnancy.  We will specifically ask you to let us know if you change 
your mind and decide to become pregnant during the study. 
 
Benefits 
While it is unlikely that a single dose will have a significant effect, you may experience mild beneficial 
effects from the green tea extract L-theanine, including a sense of calm, relaxation, and reduced level of 
anxiety, on the day you are given the active drug. 
 
Economic Considerations   
You will be paid in the form of gift cards as follows:  $20 for completion of the first visit; $50 for 
completion of the second visit and $80 for finishing the third and last visit. Therefore, you will receive 
$150 in total if you completed the whole study (for about 7 hours in total of your time). All monetary 
compensation will be given to you in a form of gift cards. The one dose of L-theanine or placebo will be 
provided by the researchers. 
 
Alternative Treatments/Alternative to Participation 
N/A. No treatments are being offered in this study.  
 
In Case of Injury   
We will offer you services in Care New England facilities as needed to treat any injury that results directly 
from taking part in this research study.  We reserve the right to bill your insurance company or other 
third parties, if appropriate, for the care you get for the injury.  We will try to have these costs paid for, 
but you may be responsible for some of them.  For example, if the care is billed to your insurer, you will be 
responsible for payment of any deductibles and co-payments required by your insurer.   
 
Injuries sometimes happen in research even when no one is at fault.  There are no plans to pay you or give 
you other compensation for any injury, should one occur.  However, you are not giving up any of your 
legal rights by signing this form.   
 
If you think you have been injured or have experienced a medical problem as a result of taking part in this 
research study, tell the person in charge of this study as soon as possible.  The researcher’s name and 
phone number are listed on the last page of this consent form.    
 
Financial Disclosure   
N/A. There is no industry support for this research study 
 


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Voluntary Participation 
You are free to decide whether or not to participate in this study, and you are free to withdraw from the 
study at any time.  A decision not to participate or to withdraw from the study will not adversely affect 
your current or future interactions with Butler Hospital or Care New England. Your participation in the 
study may be terminated by the researchers without regard to your consent; in that case, you are entitled 
to an explanation of the conditions leading to that decision. 
 
Confidentiality  
Personal identifiers will be removed from any identifiable private information about you in the final 
research dataset created by this study. You will not be personally identified in any reports or publications 
that may result from this study.  The confidentiality of the information you provide to us will be 
maintained in accordance with state and federal laws.  If you tell us something that makes us believe that 
you or others have been or may be physically harmed, we may report that information to the appropriate 
agencies. To keep your information safe, all data will be stored on password protected computers, as well 
as on Care New England’s REDCAP secure database and research servers.   
   
General information about this study has been or will be submitted to the federal clinical trial registry 
databank, which can be accessed on the Internet at www.ClinicalTrials.gov. 
 
Authorization for use/disclosure of your Identifying Health Information, to Conduct this Research 
Study 
If you sign this document, you give permission to the researchers (Dr. Shiwen Yuan, Dr. Linda Carpenter, 
and the Neuromodulation Research Facility Assistants) at Butler Hospital to use your health information 
that identifies you, for the purpose of conducting the research study described above.  
 
Your health information may also be shared with a public health authority that is authorized by law to 
collect or receive such information for the purpose of preventing or controlling disease, injury, or 
disability, and conducting public health surveillance, investigations, or interventions.  
 
Butler Hospital is required by law to protect your health information. Individuals outside of Butler that 
receive your health information may not be required by Federal privacy laws (such as the HIPAA Privacy 
Rule) to protect it, so we cannot guarantee that they will not share it without your permission. 
 
 
Please note that:  
• 
You do not have to sign this consent form, but if you do not, you may not participate in or receive 
research-related treatment in this study.   
• 
Butler Hospital may not withhold treatment or refuse to treat you, based on whether you sign this 
consent form.  
• 
You may change your mind and revoke (take back) this consent and authorization at any time. If 
you no longer want to give us permission to use your health information for this research study, 
you must contact the Principal Investigator, Dr. Linda Carpenter, and you will be instructed to 
provide a written statement.  
• 
Even if you revoke (take back) this consent and authorization, Butler researchers may still use or 
share health information about you that they already have obtained, when doing so is necessary 
to maintain the integrity or reliability of the current research.  
• 
You generally will not have access to your personal health information related to this research 
until the study is completed. At the conclusion of the research and at your request, you will have 
access to your health information that Butler Hospital maintains in a designated record set, 
according to the Notice of Privacy Practices provided to you by Butler Hospital. The designated 


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record set includes medical information or billing records used by doctors or other health care 
providers at Butler Hospital to make decisions about individuals.  
• 
Your health information will be provided to you or to your physician if it is necessary for your 
care.  
• 
If all information that does or can identify you is removed from your health information, the 
remaining information will no longer be subject to this authorization and may be used or 
disclosed for other purposes. 
 
This Authorization does not have an expiration date.  
 
Questions 
Taking part in this study is entirely voluntary. We urge you to discuss any questions about this study with 
our staff members. You should take as much time as you need to make your decision. If you decide to 
participate, you must sign this form to show that you want to take part.  
 
 


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Authorization:   
I have read this form and decided that I _________________________________________________________________ 
 
 
 
 
 
 
 
 (printed name of participant) 
will participate in the project described above.  Its general purposes, the nature of my involvement, and 
possible hazards and inconveniences have been explained to my satisfaction.  
I have received a copy of this consent form. 
__________________________________________________________ 
 
_____________________________________ 
Signature of Participant 
 
 
 
 
Date 
 
 
 
 
__________________________________________________________ 
 
_____________________________________ 
Signature of Principal Investigator 
 
 
 
Date 
 
 
 
 
~or~ 
__________________________________________________________ 
 
_____________________________________ 
Signature of Person Obtaining Consent 
 
 
Date 
Telephone Number of Principal Investigator or Person Obtaining Consent_________________________ 
 
If you have further questions about this project or about research-related injuries, please contact Shiwen 
Yuan, M.D. at 401-455-6436 or Linda Carpenter, M.D. at 401-455-6349.  If you have questions about your 
rights as a research subject, please contact Paul F. Malloy, Ph.D., Vice Chair, Butler Hospital Institutional 
Review Board, at 401-455-6355. 
 
THIS FORM IS NOT VALID UNLESS THE FOLLOWING BOX HAS BEEN COMPLETED BY THE IRB OFFICE 
 
THIS FORM IS VALID UNTIL 
 
 
    DATE:  
 
 
    IRBNET ID#  
    BUTLER IRB REFERENCE# 
 
 
    BY (ADMINISTRATOR):