Prevalence of and factors associated with antipsychotic polypharmacy in patients with serious mental illness: Findings from a cross-sectional study in an upper-middle-income country

Objective: The aim of our study was to examine the prevalence of and factors associated with antipsychotic polypharmacy (APP) among patients with serious mental illness in the current South African health care context. Methods: We collected data on patient, illness, and treatment characteristics of patients discharged on one or more antipsychotic agents from January to June 2014. We analyzed the associations of APP with demographic and clinical variables using hierarchical multivariable logistic regression, and examined prescription patterns. Results: The prevalence of APP in our study population of 577 patients was 28.4%. Demographic and clinical characteristics significantly associated with APP included age > 29, male sex, diagnosis of schizophrenia, comorbid intellectual disability, comorbid substance use, greater number of hospital admissions, and high-dose prescribing. First-generation antipsychotics and long-acting injectable preparations were prominent in APP combinations. Co-prescription of anticholinergic agents and sodium valproate demonstrated a significant association with APP. Conclusion: APP appears common in our population, despite lack of evidence for the practice and possible risk of harm. Our findings suggest a complex interplay among patient, illness, and treatment factors relevant to APP in our setting that could be targeted for intervention.