Cognitive deficits worsen quality of life and raise dementia risk in Parkinson’s disease (PD) psychosis, but the trajectory has been unclear. Using Parkinson’s Progression Markers Initiative data, researchers followed 676 drug-naïve patients with PD and 187 healthy controls over 5 years, classifying PD participants who developed psychosis (PDP) versus those who did not (PDnP) via the Movement Disorders Society Unified Parkinson’s Disease Rating Scale part I hallucinations/psychosis item. Repeated cognitive assessments spanned memory, visuospatial skills, language/fluency, processing speed, and global cognition. Change was modeled with linear mixed effects, adjusting for age, sex, ethnicity, education, and neuropsychiatric/PD variables to reduce confounding.
At baseline, PDP and PDnP did not differ cognitively, and PD performed worse than controls on most tests. Over 5 years, however, PDP showed steeper declines than PDnP across immediate and delayed recall, global cognition, visuospatial ability, semantic fluency, and processing speed. These differences persisted after adjustments for depression, daytime sleepiness, rapid eye movement sleep behavior disorder, and motor severity, implicating psychosis emergence as a marker of accelerated, domain-wide cognitive deterioration. These results argue for closer cognitive surveillance when psychosis appears, incorporation of cognitive endpoints in PD psychosis trials, and earlier, targeted interventions to mitigate downstream functional impact.
Reference: Pisani S, Gosse L, Aarsland D, et al. Parkinson’s disease psychosis associated with accelerated multidomain cognitive decline. BMJ Ment Health. 2024;27(1):1-10. doi: 10.1136/bmjment-2024-301062.
