Researchers of this Bayesian meta-analysis compared cognitive performance in Parkinson’s disease with psychosis (PDP) versus without psychosis (PDnP) across 105 studies. Using Hedges’ g as the effect size, PDP showed worse performance across nine cognitive domains. The largest and most consistent impairments were in global cognition (k=103, g≈−0.57), processing speed (k=29, g≈−0.58), executive functions (k=33, g≈−0.56), episodic memory (k=30, g≈−0.58), and perception (k=34, g≈−0.55).
Meta-regressions indicated that age, depression, and disease duration moderated performance across many domains, while dopamine replacement dose did not. The authors also report deficits—though generally smaller—in attention/working memory, language, and visuospatial abilities, with several executive and perceptual subdomains showing consistent impairment. Clinically, these findings support routine cognitive screening in PDP, targeted management of comorbid depression, and consideration of non-dopaminergic mechanisms when planning care. The results argue for integrating cognitive rehabilitation and caregiver support into PDP management, while acknowledging heterogeneity across studies and the need for longitudinal work to clarify trajectories and causality.
Reference: Pisani S, Gosse L, Wieretilo R, et al. Cognitive and executive impairments in Parkinson’s disease psychosis: a Bayesian meta-analysis. J Neurol Neurosurg Psychiatry. 2024;95(3):277-287. doi: 10.1136/jnnp-2022-331028.
