The Effects of Non-invasive Brain Stimulation on Treatment Adherence in Schizophrenia

Study Overview
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Brief Summary
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This study seeks to explore the effects of transcranial direct current stimulation (tDCS), a non-invasive method of brain stimulation, as an adjunctive treatment to improve antipsychotic medication adherence in patients with schizophrenia (SCZ). The investigators hypothesize that 20 sessions of tDCS will improve medication nonadherence in patients with SCZ.

Detailed Description
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The proposed study will investigate the effects of adjunctive tDCS on antipsychotic medication adherence by targeting brain regions implicated in impaired insight, a primary contributor to medication nonadherence in patients with SCZ. Participants will be randomized to receive either active or sham tDCS. tDCS will be administered twice-daily for 10 days (20 sessions) excluding weekends. Brain scans will be performed before and after 10 days of tDCS. Antipsychotic drug adherence will be assessed based primarily on pill-count, and secondarily, plasma level concentrations and clinician-judgement.

Official Title
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The Effects of Adjunctive Transcranial Direct Current Stimulation on Treatment Adherence in Schizophrenia

Conditions
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Schizophrenia;Schizoaffective

Intervention / Treatment
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* Other: Active TDCS
* Other: Sham TDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female participants of any race or ethnicity Inpatients or outpatients ≥18 years of age DSM-V diagnosis of SCZ or schizoaffective disorder Capable of consenting to participate in the research study On a stable dose of antipsychotic drug and other concomitant medications for at least 2 months, and unlikely to undergo changes in dose during the study Exclusion Criteria: Unwilling or incapable to consent to the study based on the MacArthur Test of Competence Unstable medical or any concomitant major medical or neurological illness, including a history of seizures Acute suicidal or homicidal ideation Formal thought disorder rating ≥3 on the Positive and Negative Syndrome Scale (PANSS) P2 conceptual disorganization item DSM-V substance dependence (except caffeine and nicotine) within 1 month of entering the study* Positive urine drug screen except for cannabis/marijuana at the screening visit Metal implants or pacemaker precluding an MRI scan or other contraindications to MRI (eg., claustrophobia) Pregnancy Score < 32 on the Wide Range Achievement Test-III Substance misuse: In addition to impaired insight, substance misuse is one of the principle contributors to medication nonadherence. To minimize the possibility of its influence, participants with a DSM-V diagnosis of substance dependence within 1 month of entering the study or a positive urine drug test (except for cannabis/marijuana) at the screening visit will be excluded. Substance use and urine drug screens will be assessed at subsequent study visits.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participant randomly assigned to receive either TDCS stimulation or sham stimulation.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Active TDCS<br>In the active condition, a constant current of 2 mA intensity will be applied for 20 min to the parietal regions, using P3 as the cathode and P4 as the anode. | Other: Active TDCS<br>* Participants will receive active TDCS stimulation.<br>|
| Sham Comparator: Sham TDCS<br>In the sham condition, stimulation will be administered using the same parameters at the site of active treatment, but the current will be turned off after 30 seconds. | Other: Sham TDCS<br>* Participants will receive sham TDCS stimulation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Medication adherence - Pill Count | Pill count or percentage of weekly antipsychotic medication adherence will be assessed during the 3-month follow up phase after TDCS is completed. | During 3-month follow up phase | 
| Medication adherence - Plasma Monitoring | Blood concentrations of antipsychotic medication will be measured at different points in the study to assess medication adherence. | Blood concentration of antipsychotic medication will be measured on day of the first TDCS session before TDCS starts, after 1 week of TDCS is completed, after 2 weeks of TDCS are completed, and during the 3-month follow up phase. | 
| Medication adherence - Clinician Rating | The Clinician Adherence Rating Scale is a 7-point clinician rated measure which takes into account patients' self-report, medication adherence, and changes in plasma concentrations to provide a comprehensive assessment of antipsychotic medication adherence. A higher score represents greater adherence. | During 3-month follow up phase | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Insight into Psychosis | Level of illness awareness will be assessed by the VAGUS Insight into Psychosis scale. The VAGUS assesses the core domains of insight into psychosis. VAGUS has both self-report and clinician-rated versions with good inter-scale reliability and test-retest reliability. Higher scores indicate better insight into illness. | Illness awareness will be assessed before the TDCS phase begins, after 2 weeks of TDCS are completed, and during the 3-month follow up period | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Magnetic resonance imaging, Brain stimulation, Medication adherence