Background. Studies that assess the rates of psychotic patients who fail to adhere to treatment programmes have generated heterogeneous results, with estimates ranging from 24 to 90%. This paper presents findings from a systematic review on adherence to treatment by patients with psychosis. Its purpose is to provide an overall estimate of treatment non-adherence in community psychiatric services, and to analyse and study patient characteristics explaining the between-study heterogeneity in rates of non-adherence.

Method. A systematic review of published studies that report rates of non-adherence with medication and scheduled appointments by psychotic patients in community settings has been undertaken.

Results. A total of 103 studies were included in this systematic review. Eighty-six of these studies were suitable for data re-analysis. The overall weighted mean rate of non-adherence, calculated in a sample of 23796 patients, was 25·78%. A linear regression analysis of non-adherence rates on background characteristics showed that sample size was negatively associated with non-adherence rates, while first-contact cases and low-adherence cases, in comparison with ongoing cases, were associated with higher non-adherence rates. Factors associated with poor compliance included: lack of insight; positive symptoms; younger age; male gender; history of substance abuse; unemployment; and low social functioning.

Conclusions. Approximately one in four patients with psychosis fails to adhere with treatment programmes. Preventive evidence-based clinical interventions should be routinely implemented in community settings to reduce patient non-adherence.