After adjusting for anxiety and depressive symptoms, obsessive-compulsive symptoms were still associated with symptoms of alcohol dependence, both concurrently (for alcohol use, β = 0.12 [95% CI, 0.09-0.14]; for drug use, β = 0.12 [95% CI, 0.04-0.20]) and longitudinally (for alcohol use, β = 0.05 [95% CI, 0.00-0.09]; for drug use, β = 0.11 [95% CI, 0.00-0.22]). Further, obsessive-compulsive symptoms remained associated with alcohol dependence symptoms at 24 years of age when we accounted for alcohol dependence symptoms at 18 years of age (β = 0.05 [95% CI, 0.01-0.09]).