A randomized controlled trial of quetiapine for psychosis in Parkinson’s disease

INTRODUCTION Psychosis (delusions and/or hallucinations) is a well-recognized complication of treatment of Parkinson's disease (PD). Quetiapine is a currently favored treatment, but data on its efficacy are equivocal. This trial aimed to provide further evidence on the efficacy of quetiapine in PD psychosis. METHODS We conducted a 12 week double blind randomized placebo-controlled trial. Time to dropout due to lack of improvement of psychosis was the primary outcome measure. Other important secondary outcomes were evaluated using standard rating scales for PD and psychiatric symptoms. RESULTS Twenty-four eligible subjects gave consent. The primary outcome, time to dropout, was examined using survival analysis. It was shown that patients in the quetiapine group dropped out earlier than those in the placebo group, but this difference was not significant (p = 0.68). No significant changes were found for any of the secondary outcome measures in either group. CONCLUSIONS In this study, quetiapine at doses of up to 150 mg/day failed to significantly improve psychosis compared to placebo, however the small sample size does not allow any conclusive interpretation of the results. Quetiapine did not appear to worsen PD motor functioning, but its use was limited by a faster drop out compared with placebo. Significant impediments were difficulty with recruitment and natural fluctuation in symptoms during the trial.