Movement Disorder Society - Dublin, Ireland
Objective: To determine the frequency of impulse control disorder (ICD) symptoms and related behaviors in a cohort of de novo, untreated Parkinson disease (PD) patients and healthy controls (HCs).
Background: An association between PD medications and a range of ICDs in PD patients isestablished, but it is unknown if PD itself confers an altered risk of ICD expression compared with the general population.
Methods: Data was gathered as part of the Parkinson's Progression Markers Initiative (PPMI). At baseline de novo, untreated PD patients and similarly-aged HCs were administered the short form of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP), which queries for compulsive gambling, buying, sexual behavior and eating, as well as punding and hobbyism. Between-group difference in ICD frequencies were examined with the chi-squared test and logistic regression models.
Results: 280 participants with complete data were assessed (PD=155, HC=125). There was no statistically significant difference in age (PD=61.4 years vs. HC=59.0 years; t=1.78 (df=234), p=0.08), but PD patients were more likely to be male (71.4% vs. 50.4%, χ2=13.2 (df=1), p<0.001). Frequencies of positive QUIPs for PD patients versus HCs were: gambling (0.6% vs. 0.8%), buying (2.6% vs. 0.8%), sexual behavior (4.5% vs. 3.2%), eating (7.1% vs. 9.6%), any ICD (11.0% vs. 11.2%), punding (5.8% vs. 2.4%), hobbyism (5.8% vs. 11.2%), and any ICD or related behavior (19.4% vs. 18.4%); none of these differences were statistically significant. In logistic regression models that controlled for age and sex, PD patients were not more likely to experience an ICD (B= -0.83 (SE=0.40), p=0.84) or an ICD or related behavior (B= -0.12 (SE=0.32), p=0.71).
Conclusions: These results suggest that PD itself does not confer an increased risk for development of ICD symptoms and related behaviors, which reinforces the reported association between PD medications and ICDs in PD. Given that approximately 20% of untreated PD patients screen positive for ICD or related symptoms, long-term follow-up of the PPMI cohort will determine if such patients are at increased risk of ICD development when PD medications are initiated.
Authors: Daniel Weintraub, Kimberly Papay, Andrew Siderowf