Clozapine for acute and maintenance treatment of psychosis in Parkinson's disease.

In a prospective, open-label study, 12 patients manifesting psychosis associated with Parkinson's disease were treated with clozapine. Cognitive functioning and type of psychotic symptoms were measured prior to treatment, and changes in psychiatric and behavioral symptoms were studied by using the Behave-AD Scale. Significant resolution in psychotic symptoms was found and improvement in global behavioral status observed in all cases, with 10 patients maintaining improvement at follow-up. Careful initiation and titration of the drug resulted in few side effects, and dementia was not found to be a contraindication to such treatment.