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

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

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.

Study Overview

• Status: Recruiting
• Conditions: Schizophrenia;Schizoaffective
• Intervention / Treatment: Other: Active TDCS; Other: Sham TDCS

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 106
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Philip Gerretsen, MD, PhD; Phone Number: 39426 416-535-8501; Email: philip.gerretsen@camh.ca
• Study Contact Backup: Name: Ariel Graff, MD, PhD; Phone Number: 34834 416-535-8501; Email: ariel.graff@camh.ca

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5T 1R8
      • Recruiting
      • Centre for Addiction and Mental Health
      • Contact: Philip Gerretsen, MD, PhD; Phone Number: 39426 416-535-8501; Email: philip.gerretsen@camh.ca
      • Contact: Ariel Graff, MD, PhD; Phone Number: 34834 416-535-8501; Email: ariel.graff@camh.ca

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Male or female participants of any race or ethnicity
2. Inpatients or outpatients ≥18 years of age
3. DSM-V diagnosis of SCZ or schizoaffective disorder
4. Capable of consenting to participate in the research study
5. 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:

1. Unwilling or incapable to consent to the study based on the MacArthur Test of Competence
2. Unstable medical or any concomitant major medical or neurological illness, including a history of seizures
3. Acute suicidal or homicidal ideation
4. Formal thought disorder rating ≥3 on the Positive and Negative Syndrome Scale (PANSS) P2 conceptual disorganization item
5. DSM-V substance dependence (except caffeine and nicotine) within 1 month of entering the study*
6. Positive urine drug screen except for cannabis/marijuana at the screening visit
7. Metal implants or pacemaker precluding an MRI scan or other contraindications to MRI (eg., claustrophobia)
8. Pregnancy

9. 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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active TDCS; 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; Participants will receive active TDCS stimulation.
Sham Comparator: Sham TDCS; 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; Participants will receive sham TDCS stimulation.

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Centre for Addiction and Mental Health
• Investigators: Principal Investigator: Philip Gerretsen, MD, PhD, Centre for Addiction and Mental Health

Publications and helpful links

Helpful Links

• The Centre for Addiction and Mental Health (CAMH) is the leading mental health and addictions research facility in Canada, and one of the largest in the world.

Study record dates

Study Major Dates

• Study Start (Actual): August 15, 2019
• Primary Completion (Estimated): December 31, 2024
• Study Completion (Estimated): December 31, 2024

Study Registration Dates

• First Submitted: May 23, 2019
• First Submitted That Met QC Criteria: July 24, 2019
• First Posted (Actual): July 26, 2019

Study Record Updates

• Last Update Posted (Actual): September 15, 2023
• Last Update Submitted That Met QC Criteria: September 14, 2023
• Last Verified: September 1, 2023

More Information

Terms related to this study

• Keywords: Magnetic resonance imaging; Medication adherence; Brain stimulation
• Additional Relevant MeSH Terms: Mental Disorders; Schizophrenia Spectrum and Other Psychotic Disorders; Schizophrenia
• Other Study ID Numbers: 103-2018

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No