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Keywords:

  • Risperidone;
  • Parkinson's disease;
  • Psychosis;
  • Extrapyramidal symptoms

Abstract

PURPOSE

To evaluate the safety and efficacy of risperidone in patients with Parkinson's disease (PD) who are experiencing significant dopamine-induced 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 per day. Maintenance antiparkinsonian medication was continued throughout, although psychotropic medication was discontinued.

EFFICACY RESULTS

Risperidone produced a substantial improvement in psychotic symptoms, shown on the mean total positive subscale score on the Positive 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 improvement was most evident in the items delusions, hallucinatory behavior, and suspiciousness/persecution. Risperidone also achieved significant improvement from baseline in Clinical Global Impression (CGI)-severity and CGI-improvement (p <0.001, Page test). Risperidone treatment did not adversely affect symptoms specific to Parkinson's disease, as assessed by the Unified Parkinson's Disease Rating Scale (UPDRS).

SAFETY RESULTS

Sixteen patients reported at least one adverse event, but only two patients withdrew as a result of adverse events. No significant changes or clinically relevant abnormalities were observed in laboratory parameters or vital signs.

CONCLUSION

Short-term use of risperidone (mean dosage, 1.1 mg per day) improves the psychopathology of patients with PD who have dopamine-induced psychosis without adversely affecting the symptoms of PD. Higher doses and long-term use were not addressed in this study and may be precluded by extrapyramidal side effects.