Panish, J., S. Karve, S.D. Candrilli, and R. Dirani. (2013). "Association between adherence to and persistence with atypical antipsychotics and psychiatric relapse among US Medicaid-enrolled patients with schizophrenia." Journal of Pharmaceutical Health Services Research, 4(1):29-39.

Assess association between adherence and persistence with second-generation oral antipsychotics (SGOAs), psychiatric-related relapse and healthcare utilization among patients with schizophrenia experiencing two or more psychiatric-related relapses.
A retrospective analysis of the US Medicaid Multi-State Database for 2004–2008. Patients with schizophrenia (aged 18–64) with two or more psychiatric-related relapses within 1 year after SGOA initiation were selected. Associations between a dichotomous measure of adherence and persistence with SGOAs and psychiatric-related relapse and healthcare utilization were assessed using unadjusted and covariate-adjusted regression models. No adjustment was made for multiplicity.
Key findings
Study cohort consisted of 3714 patients with mean age of 42.6 years. Overall, 45% of patients were adherent and 50% persistent with SGOAs. Unadjusted and covariate-adjusted analysis results suggested the 12-month psychiatric-related relapse rate was lower among adherent/persistent patients versus non-adherent patients (unadjusted mean: 3.85 versus 4.13; P?Conclusions
Although SGOAs have proven efficacy in lowering the rate of psychiatric-related relapses, lower adherence and persistence rates may be an inhibiting factor in achieving optimal benefits from SGOAs. Future research is needed to assess whether newer antipsychotics with less-frequent dosing may improve adherence among patients with schizophrenia.