Past smoking and current dopamine agonist use show an independent and dose-dependent association with impulse control disorders in Parkinson's disease

Background: Previous studies have described the association between dopamine replacement therapy in Parkinson's disease and impulse control disorders. Methods: A case control study was performed to establish the prevalence of four of these behaviors in Brazilian patients with Parkinson's disease on stable dopamine replacement therapy and the possible associated risk factors. We investigated 152 patients and 212 healthy controls for pathological gambling, compulsive sexual behavior and compulsive buying and eating. Results: Overall, patients had more impulsive control disorders than controls (18.4% vs. 4.2%, P < 0.001). Impulse control disorders were more common in younger patients (P = 0.008) and in those taking dopamine agonist (P < 0.001) and levodopa (P = 0.02). Higher Unified Parkinson's Disease Rating Scale motor score (P = 0.03) and past smoking (P = 0.02) were also associated in the univariate analysis. Variables independently associated with impulse control disorders were history of smoking (odds ratio = 1.059 for each year of smoking, P = 0.010) and current use of pramipexole (odds ratio = 2.551 for each increase in 1 mg, P < 0.001). Conclusions: Dopaminergic stimulation and previous exposure to smoking are independently associated with impulse control disorders in a dose-dependent manner. (c) 2013 Elsevier Ltd. All rights reserved.