Authors of this systematic review examined whether neuropsychiatric symptoms (NPS) in Parkinson’s disease are linked to worse cognitive functioning in patients without dementia. Across 11 studies involving 3,865 participants, most found that patients with Parkinson’s disease and NPS performed worse cognitively than those without NPS, particularly in global cognition, memory, attention, executive function, language, visuospatial ability, and processing speed. The authors emphasize that these symptoms often cluster together rather than occurring in isolation. Patterns such as apathy, anxiety, depression, psychosis, and other behavioral changes may signal increased cognitive vulnerability even in early or newly diagnosed disease. Studies using more detailed neuropsychological testing were generally better able to detect these differences than those relying only on broad screening tools such as the Mini-Mental State Examination or Montreal Cognitive Assessment.

The authors conclude that neuropsychiatric symptoms should be considered an important part of clinical evaluation in Parkinson’s disease because they may help identify patients at greater risk for cognitive decline. Tools such as the Mild Behavioral Impairment Checklist may be especially useful for detecting subtle behavioral changes before overt dementia develops. At the same time, the review notes important limitations, including the small number of eligible studies, substantial methodological differences across them, and the lack of enough comparable data to perform a meta-analysis. Overall, the evidence supports a meaningful association between NPS and poorer cognition in Parkinson’s disease. It also highlights the need for larger, more standardized longitudinal studies to better define this relationship and guide earlier intervention.

Reference: Blasutto B, Matrone G, Creese B, Fattapposta F, Casagrande M. Neuropsychiatric symptoms and their impact on cognitive functioning in patients with parkinson’s disease: A systematic review of the literature. Cogn Affect Behav Neurosci. 2026 Mar 26. doi: 10.3758/s13415-026-01424-2. Epub ahead of print. PMID: 41888329.

Link: https://link.springer.com/article/10.3758/s13415-026-01424-2