Treating dopamimetic psychosis in Parkinson's disease: structured review and meta-analysis.

Psychosis due to dopamimetic treatment is a difficult problem in patients with Parkinson's disease (PD). The aim of this structured review with meta-analysis was to evaluate which neuroleptic drugs can efficiently be used to treat drug-induced psychosis (DIP) in Parkinson's disease. Electronic databases were screened for the key words Parkinson's disease and psychosis. Only 7 trials with a satisfactory allocation concealment and data reporting were included into the study. Two trials compared low-dose clozapine versus placebo with a significantly better outcome for clozapine regarding efficacy and motor functioning. In one trial clozapine was compared against quetiapine showing equivalent efficacy and tolerability. However, in two placebo controlled trials quetiapine failed to show efficacy. In two further placebo controlled trials olanzapine did not improve psychotic symptoms and significantly caused more extrapyramidal side effects. Based on randomized trial-derived evidence which is currently available, only clozapine can be fully recommended for the treatment of DIP in PD. Olanzapine should not be used in this indication.