A Comparison of Cognitive Performance in Patients With Parkinson's Disease Psychosis According to Psychosis Severity: A Meta-Analysis

Aims People with Parkinson's disease psychosis (PDP) have reported cognitive and executive deficits. However, it is unclear whether these deficits are different depending on severity. Here, we aimed to compare performance between PDP patients varying severity of their symptoms (such as delusions hallucinations), relative without (PDnP), using a meta-analytical approach. Methods Searches were conducted PubMed, MEDLINE, Web Science, PsycINFO SCOPUS. Standard mean differences PDnP function tests expressed Hedges’ g effect sizes from eligible studies (K = 23). classified based the into formed unformed hallucinations, hallucinations with/without insights. Separate multi-level meta-analyses for symptom groups patients, domains due contributing multiple domains. Meta-regressions examine age. Analyses in R (version 4.2.2). Results negative all analyses, suggesting that (n 317) showed significantly worse than 734) across (global cognition, g=−0.853, p < 0.001; language, g=−0.602, episodic memory, g=−0.899, functions, g=−0.543, 0.007; processing speed, g=−0.698, 0.001). There was presence significant heterogeneity analyses (all 0.05), except language (p 0.053) speed 0.077). also publication bias (assessed Egger's regression test) 0.001), global cognition 0.656). 135) performed same but results not significant. Publication 0.4054). Age shown be moderator b=−0.02, 0.13; b=−0.042, 0.037; b=−0.055, b=−0.098, b=−0.048, 0.022). Relative 322), both insights had scores (no insights, n 37, g=−2.747, 0.021; 83, g=−0.942, 0.019). Due low number (k 7), test applied. Conclusion Decreased may underlie impairments patients. Formed lack associated greater In addition, older age could result scores.