A recent controlled clinical trial suggested a role for amantadine as a treatment for pathological gambling in patients with Parkinson disease (PD). Analyzing data from a large cross-sectional study of impulse control disorders (ICDs) in PD, amantadine use (n = 728), vs no amantadine use (n = 2,357), was positively associated with a diagnosis of any ICD (17.6% vs 12.4%, p < 0.001) and compulsive gambling specifically (7.4% vs 4.2%, p < 0.001). This amantadine association remained after controlling for covariates of amantadine use, including both dopamine agonist use and levodopa dosage. Further research, including larger clinical trials, is needed to assess the role of amantadine in the development and treatment of ICDs in PD. Ann Neurol 2010