Impulse control disorders in Parkinson disease: a multicenter case--control study.

OBJECTIVE: To assess factors associated with impulse control disorders (ICDs) in Parkinson disease (PD) using a multicenter case--control design.
METHODS: Patients enrolled in the DOMINION study, a multicenter study assessing the cross-sectional frequency of ICDs in PD, were eligible to participate in the case--control study. PD patients with and without an ICD (n = 282 each) (compulsive gambling, buying, sexual behavior, and eating) were matched individually on age, gender, and dopamine agonist treatment. Subjects were assessed with a comprehensive neurological, psychiatric, and cognitive assessment battery.
RESULTS: ICD patients reported more functional impairment (p < 0.001); greater depressive (p < 0.0001), state (p < 0.0001), and trait (p < 0.0001) anxiety; greater obsessive-compulsive symptoms (p < 0.0001); higher novelty-seeking (p < 0.001) and impulsivity (p < 0.001); and differences in reward preference reflecting greater choice impulsivity (p < 0.05). Patients with multiple ICDs had greater dyskinesia scores compared to those with single ICDs.
INTERPRETATION: ICDs in PD are associated with multiple psychiatric and cognitive impairments, including affective and anxiety symptoms, as well as elevated obsessionality, novelty seeking, and impulsivity. These results highlight the importance of assessing multiple mental health domains in individuals with PD and ICDs, and suggest possible pathophysiological mechanisms and risk indicators for these disorders.