Prevalence of and indications for antipsychotic use in Parkinson's disease.

BACKGROUND: The prevalence of patients with PD taking antipsychotics is unknown.
OBJECTIVE: To measure the prevalence of patients with PD taking antipsychotics.
METHODS: We used the medical records-linkage system of the Rochester Epidemiology Project to study the use of antipsychotic medication in all persons with Parkinson disease in Olmsted County, Minnesota on 1 January 2006.
RESULTS: There were 296 patients with PD in Olmsted County on 1 January 2006. The overall prevalence of antipsychotic use was 9.8% (29 of 296); 95.5% (28 of 29) of the patients had dementia when initiating antipsychotics. The most frequent indication (71.4%; 20 of 28) was psychosis or behavior threatening to the patient or others.
CONCLUSIONS: The prevalence of antipsychotic use in patients with PD is lower than expected from previously reported cumulative incidences. Dementia is highly prevalent in those starting antipsychotics. Most of the patients on antipsychotics had a reasonable risk-benefit ratio for taking them.