All individuals were interviewed with the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA; Bucholz et al., 1994; Hesselbrock et al., 1999), using the adult (age 18+) or adolescent (age 12–17) version as appropriate. The interviews are nearly identical, with subtle wording changes to make the language age appropriate. All diagnoses were made according to DSM-IV criteria (APA, 2000). Symptom counts for the following diagnoses were analyzed: alcohol dependence, illicit drug dependence (including marijuana, cocaine, other stimulants, sedatives, and opiates), childhood conduct disorder, and (for individuals aged ≥ 18) adult antisocial behavior. These disorders have been previously shown to share a genetic etiology (Kendler et al., 2003b) and have been previously associated with GABRA2 in the initial adult COGA sample, as reviewed above.
