This network meta-analysis assessed the efficacy, tolerability, and acceptability of second-generation antipsychotics (SGAs) for Parkinson's disease psychosis (PDP).

We searched PubMed, Embase, Cochrane Library, and ClinicalTrials.gov for randomized controlled trials investigating SGAs for PDP up to October 26, 2023.

We included 16 trials (N = 1252) investigating clozapine, melperone, olanzapine, pimavanserin, quetiapine, ulotaront, and placebo. In comparisons between SGAs and placebo, the findings were: i) Standardized mean differences, 95% confidence intervals (SMDs, 95%CIs), for psychotic-symptom reduction revealed the first rank of clozapine (−1.31, −1.73 to −0.89), the second rank of pimavanserin, with significant inferiority of quetiapine (SMD = 0.47, 0.02 to 0.92); ii) Mean differences (MDs, 95%CIs) for abnormal movement, as assessed by the Unified Parkinson's Disease Rating Scale – Part III, indicated that clozapine had the least motor side effects (−0.92, −2.75 to 0.91); iii) Risk ratios (RRs, 95% CIs) for adverse-effect dropout rates were lowest for melperone (1.02, 0.20 to 5.24); and iv) RRs (95% CIs) for all-cause dropout rates were lowest for clozapine (0.73, 0.42 to 1.25).

For patients with PDP, clozapine may substantially reduce psychotic symptoms with minimal abnormal movement, high acceptability, and moderate overall tolerability. Pimavanserin, not quetiapine, could be an alternative.