Open-label flexible-dose pilot study to evaluate the safety and tolerability of aripiprazole in patients with psychosis associated with Parkinson's disease.

Psychosis affects at least 5% to 8% of medication-treated patients with idiopathic Parkinson's disease (PD). Treatment options include reducing medications used for the treatment of PD-related motor symptoms or introducing an atypical antipsychotic drug. Only clozapine has been demonstrated to be efficacious and tolerated in double-blind controlled trials. This study evaluated the effect of aripiprazole, an atypical antipsychotic, on psychosis in PD in an open-label pilot study. Fourteen patients meeting entry criteria were started on aripiprazole 1 mg/day and titrated up to a maximum dose of 5 mg as needed. Subjects were evaluated on the Unified Parkinson's Disease Rating Scale (UPDRS) part III for motor function, the Neuropsychiatric Inventory (NPI), and the Brief Psychiatric Rating Scale (BPRS) for psychiatric response. Statistically significant improvement in mean BPRS and positive BPRS subscales occurred with open-label aripiprazole, but eight subjects discontinued the study due to worsened Parkinsonism (three), worsened psychosis (two), worsening of both (two), and lack of efficacy (one). While some patients had a favorable response, aripiprazole was associated with an exacerbation of motor symptoms. In this small study on psychosis in PD, aripiprazole did not appear promising.