Housing First Improves Adherence to Antipsychotic Medication Among Formerly Homeless Adults With Schizophrenia: Results of a Randomized Controlled Trial

Abstract

Adherence to antipsychotic medication is a significant challenge among homeless patients. No experimental trials have investigated the impact of Housing First on adherence among patients with schizophrenia. We investigated whether Housing First in congregate and scattered-site configurations resulted in superior adherence compared to usual care. Adult participants (n = 165) met criteria for homelessness, schizophrenia, and initiation of antipsychotic pharmacotherapy prior to recruitment to an unblinded, 3-arm randomized controlled trial in Vancouver, Canada. Randomization arms were: congregate Housing First (CHF) with on-site supports (including physician and pharmacy services); scattered-site Housing First (SHF) with Assertive Community Treatment; or treatment as usual (TAU) consisting of existing services. Participants were followed for an average of 2.6 years. Adherence to antipsychotic medication was measured using the medication possession ratio (MPR), and 1-way ANOVA was used to compare outcomes between the 3 conditions. Data were drawn from comprehensive pharmacy records. Prior to randomization, mean MPR among participants was very low (0.44-0.48). Mean MPR in the follow-up period was significantly different between study arms (P < .001) and approached the guideline threshold of 0.80 in SHF. Compared to TAU, antipsychotic adherence was significantly higher in SHF but not in CHF. The results demonstrate that further implementation of SHF is indicated among homeless people with schizophrenia, and that urgent action is needed to address very low levels of antipsychotic adherence in this population (trial registration: ISRCTN57595077).

Keywords: Assertive Community Treatment; homelessness; medication possession ratio.

Fig. 1.

Participant flow through screening, assessment, and allocation to study interventions. ^αIncludes approximately 100 participants deemed ineligible via an informal telephone screen, 94 participants who were ineligible after formal in-person screening, and 200 participants who were eligible for a separate study that included participants with less severe needs. ^βIncludes 11 participants who could not be located after randomization or who left the study within 1 mo following randomization to intervention. ^γEligibility criteria for the current study included participant consent to access of administrative health data, linkable health records, initiation of antipsychotic prescription prior to recruitment, and ICD-9 diagnosis of psychotic disorder. All eligible participants were followed to the study end date or death (no loss to follow-up). CHF, congregate Housing First; SHF, scattered-site Housing First; TAU, treatment as usual.