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

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.

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.