Delusions and other manifestations of psychotic behavior are common side effects in
Parkinson's disease (PD) patients chronically treated with
dopaminergic drugs.
Clozapine, a dibenzodiazepine derivative, is an
antipsychotic drug largely devoid of extrapyramidal side effects. We evaluated the effects of low doses of
clozapine on the mental and motor functions in PD patients requiring
antipsychotic treatment. Twenty-seven PD patients taking
dopaminergic drugs and who had psychotic behavior received
clozapine at 12.5 to 75 mg/d. Fifteen patients received
clozapine for 1 to 11 months (mean, 6.8 months) and seven received it for 12 to 24 months (mean, 18 months). No patient exhibited motor deterioration, and the psychotic features disappeared immediately, allowing discontinuation of
clozapine after several months in 10 patients. Fifteen patients are still receiving
clozapine and are free of psychiatric symptoms. The
clozapine treatment was discontinued after 5 days (25 mg/d) in two patients because of
somnolence. No patient developed
neutropenia.
Clozapine in low doses is effective in the treatment of
drug-induced delusions and
hallucinations in PD.