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.

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:

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.