The aims of the present study focus on extending prior work by examining the relationships among ADHD, including Inattentive (INATT) and Hyperactive/Impulsive (HYP/IMP) subtypes, conduct problems (CDP), and alcohol problems (AlcProb) in adolescence and by addressing the following questions: First, are there associations between familial and environmental risk factors (i.e., parental alcoholism, parental smoking, maternal drinking/smoking during pregnancy, low birth weight) and our four defined phenotypes: inattention (INATT), hyperactivity/impulsivity (HYP/IMP), conduct problems (CDP) and alcohol problems (AlcProb) in adolescence? Second, after adjusting for pertinent familial risk factors, what proportion of the residual variance in each of these phenotypes is due to genetic and environmental factors? Finally, after adjusting for measured familial risk, what proportion of the comorbidity among these behavioral patterns is driven by biological risk, environmental risk, or both?
