Disease-related and genetic correlates of psychotic symptoms in Parkinson's disease§


  • Funding agencies: Michael J. Fox Foundation: Edmond J. Safra Global Genetics Consortia Grant; Close to a Cure Foundation: A Fund for Parkinson's Research of Foundation for the Carolinas; NIH: R01-NS36960, Department of Veterans Affairs Merit Review Award; New York State Department of Health Wadsworth Center; The Sartain Lanier Family Foundation; and the Riley Family Chair in Parkinson's Disease.

  • Relevant conflicts of interest/financial disclosures: Stewart A. Factor has research grants from Teva Neurosciences, Ipsen, Ceregene, the Michael J. Fox Foundation, and the Consolidated Anti-aging Foundation and also was a consultant for Boehringer-Ingelheim. Eric S. Molho has received research grants from Teva Neurosciences, Allergan, EMD Serono, Impax Pharmaceuticals, and Acadia Pharmaceuticals and has received consulting fees from Allergan, Merz Pharmaceuticals, and Ipsen.

  • §

    Full financial disclosures and author roles may be found in the online version of this article.


Our aim was to examine disease-related and genetic correlates of the development of psychotic symptoms in a large population of patients with Parkinson's disease. We studied 500 patients with Parkinson's disease from the NeuroGenetics Research Consortium using logistic regression models. Predictors were demographic, clinical (motor/nonmotor features), and genetic, measured as continuous or dichotomous variables. Continuous measures were divided into population-based tertiles. Results are given as odds ratios (95% confidence intervals) for dichotomous variables and by ascending tertile for continuous variables. Psychotic symptoms were associated with increasing age: 4.86 (1.62–14.30) and 6.25 (2.09–18.74) (test for trend: P = 0.01); and duration of disease: 3.81 (1.23–11.76) and 5.33 (1.68–16.89) (test for trend: P = 0.03). For nonmotor features, we demonstrated positive trends with depression: 1.31 (0.47–3.61) and 5.01 (2.04–12.33) (test for trend: P < 0.0001); cognitive dysfunction: 0.69 (0.26–1.84) and 2.51 (1.00–6.29) (test for trend: P = 0.03); and an excess for those with sleep disorders: 2.00 (1.03–3.89) (P = 0.04). Psychotic symptoms were not associated with tremor or postural instability scores, but there was an association with freezing of gait: 3.83 (1.67–8.75) (P < 0.002). Psychotic symptoms were not associated with the presence of any examined polymorphisms in the apolipoprotein, alpha-synuclein, or microtubule associated protein tau genes. This is the largest study to examine correlates of psychotic symptoms in Parkinson's disease. We discovered a novel association with freezing of gait. We demonstrated an association with depression and duration of disease, both of which were inconsistently related in previous studies, and confirmed the association with age, cognitive dysfunction, and sleep disorders. © 2011 Movement Disorder Society