In a 3-year prospective cohort of 105 people with Parkinson’s disease (PwP) without dementia (baseline mean age 67.8; median disease duration 4.9 years; mean Montreal Cognitive Assessment 24.8), participants completed annual evaluations of motor and non-motor symptoms plus a neuropsychological battery. Parkinson’s disease psychosis (PDPsy)—defined as recurring visual illusions, sense of presence, hallucinations, or delusions for ≥1 month—was common and progressive: point prevalence rose from 31% at baseline to 39% at year 3, and 43% experienced PDPsy at some point. Visual illusions predominated (70%), followed by hallucinations (58%), underscoring that early psychosis features are often “minor” phenomena.
Generalized estimating equations run in parallel clinical and cognitive models showed that depressive symptoms uniquely increased the odds of PDPsy (OR 1.09 per point, 95% CI 1.03–1.16, p=0.004). Executive/attentional dysfunction—indexed by slower Trail Making Test B–A—was the only cognitive predictor (OR 1.43, 95% CI 1.06–1.93, p=0.018). Other routinely measured variables were not significant predictors. Together, the results suggest that mood disturbance and set-shifting/attentional control deficits flag higher near-term psychosis risk in PwP without dementia. These features may mark the transition from isolated minor experiences to more complex psychotic symptoms and highlight targets for early monitoring and intervention.
Reference: Flanigan JL, Harrison MB, Patrie JT, et al. Clinical and cognitive features associated with psychosis in Parkinson’s disease: a longitudinal study. Front Aging Neurosci. 2024;16:1463426. doi: 10.3389/fnagi.2024.1463426.
