Patterns and Trends in Antipsychotic Prescribing for Parkinson Disease Psychosis

Background: Antipsychotic (AP) use is common in Parkinson disease (PD), but APs can worsen parkinsonism, evidence for efficacy is limited, and use in patients with dementia increases mortality. Objective: To examine the frequency and characteristics, including changes over time, of AP use in a large cohort of patients with PD. Design: Using Veterans Affairs data from fiscal year (FY) 2008, rates and predictors of AP prescribing were determined for patients with PD and psychosis stratified by dementia status (N = 2597) and a comparison group of patients with dementia and psychosis without PD (N = 6907). Fiscal year 2008 and FY2002 data were compared to examine changes in AP prescribing over time. Setting: Department of Veterans Affairs outpatient facilities. Participants: Outpatients with PD and psychosis and outpatients without PD with dementia and psychosis, all receiving care at Veterans Affairs facilities in FY2002 and FY2008. Main Outcome Measure: Antipsychotic prescribing, including overall, class, and specific medications. Results: In FY2008, 50% of patients with PD having a diagnosis of psychosis were prescribed an AP. Among treated patients, the atypical AP quetiapine was most frequently prescribed (66%), but approximately 30% received high-potency APs. Clozapine was rarely prescribed (<2%). In multivariate models, diagnoses of PD and dementia were associated with AP use. Comparing FY2008 with FY2002, AP use in PD was unchanged, with decreases in risperidone and olanzapine use offset by an increase in quetiapine prescribing and the introduction of aripiprazole. Conclusions: Half of the patients with PD and psychosis receive APs, not uncommonly high-potency agents associated with worsening parkinsonism, and frequency of use has been unchanged since the black box warning for AP use in patients with dementia was issued. Recent trends are a shift to quetiapine use and the common use of aripiprazole. As psychosis and dementia are frequently comorbid in PD, safety risks associated with AP use in this population need to be assessed.