Risperidone in the treatment of dopamine-induced psychosis in Parkinson's disease: An open pilot trial

PURPOSE: To evaluate the safety and efficacy of risperidone in patients wit h Parkinson's disease (PD) who are experiencing significant dopamine-induce d psychosis. PATIENTS AND METHODS: Seventeen patients (median age, 72 yrs) participated in this 12-week, open pilot study receiving 0.5 to 3 mg oral risperidone pe r day. Maintenance antiparkinsonian medication was continued throughout, al though psychotropic medication was discontinued. EFFICACY RESULTS: Risperidone produced a substantial improvement in psychot ic symptoms, shown on the mean total positive subscale score on the Positiv e and Negative Syndrome Scale (PANSS) by a 30% improvement (-3.1 decrease) after 1 week and a 66% improvement (-6.8 decrease) at end point. This impro vement was most evident in the items delusions, hallucinatory behavior, and suspiciousness/persecution. Risperidone also achieved significant improvem ent from baseline in Clinical Global Impression (CGI)-severity and CGI-impr ovement (p <0.001, Page test). Risperidone treatment did not adversely affe ct symptoms specific to Parkinson's disease, as assessed by the Unified Par kinson's Disease Rating Scale (UPDRS). SAFETY RESULTS: Sixteen patients reported at least one adverse event, but o nly two patients withdrew as a result of adverse events. No significant cha nges or clinically relevant abnormalities were observed in laboratory param eters or vital signs. CONCLUSION: Short-term use of risperidone (mean dosage, 1.1 mg per day) imp roves the psychopathology of patients with PD who have dopamine-induced psy chosis without adversely affecting the symptoms of PD. Higher doses and lon gterm use were not addressed in this study and may be precluded by extrapyr amidal side effects.