Delusions and hallucinations correlates in Parkinson's disease psychosis

Abstract

<h3>Introduction</h3> Patients with Parkinson disease (PD) can experience hallucinations (spontaneous aberrant perceptions) and illusions (misinterpretations of real perceptual stimuli). Of such phenomena, visual hallucinations and illusions are the most frequently encountered, although auditory, olfactory and tactile hallucinations can also occur. Hallucinations can have substantial psychosocial effects and, historically, were the main reason for placing patients in nursing homes. Concomitant or overlapping mechanisms are probably active during visual hallucinations, and these include the following: central dopaminergic over-activity and an imbalance with cholinergic neurotransmission; dysfunction of the visual pathways, alterations of brainstem sleep-wake and dream regulation; and impaired attention focus.The aim of this is to present epidemiological, genetic and pathophysiological aspects of psychosis in PD. <h3>Methods</h3> Pacific Northwest Udall Center (PANUC) was analyzed. MOCA was used to assess cognition and the NPI to examine neuropsychological symptoms including psychosis. Patients with PD without hallucinations or delusions served as controls Comparing characteristics of the PD cohort according to having either no psychosis or delusions with or without hallucinations (using the 10-item Neuropsychiatric Inventory (NPI).Chi-square test was applied to compare categorical variables; Fisher's exact test was applied to compare categorical variables when cell frequency is less than 5. Categorical factors were presented as frequencies (percentages). Unavailable logistic regression models were employed to assess association between predictors and outcome.All tests was two-tailed and performed at a significance level of 0.05. R version 3.5.1 (The R Foundation for Statistical Computing, Vienna, Austria) was used for all analyses. <h3>Results</h3> 129 persons (11% of analyzed sample) were included to the study. Of the entire patient's who reported psychotic symptoms: (84%) experienced hallucinations without delusions, (36%) had symptoms dominated by delusions. Severity and/or number of hallucination subtypes were significantly correlated with lower scores in language, memory, attention, executive functioning, and visuospatial ability. Correlations with delusions were non-significant. Tests of differences in the size of the correlations between groups revealed a significant relationship between language and visuospatial performance with hallucinations. Results suggested a significant association between APOE4 status and hallucinations. Compared to APOE4 non-carrier, APOE carrier patients have 4.509 times of odds to develop hallucinations. <h3>Conclusions</h3> Genetic and cognitive correlates of hallucinations and delusions appear to be different in PD, suggesting distinct pathogenic mechanisms and possibly anatomical substrates. Hence, delusions may not share the same associations with dementia as hallucinations