Alcohol use and related problems were measured by computerized questionnaires during in-person clinic sessions. Items that measured alcohol use and related problems were adapted from the Semi-Structured Assessment of the Genetics of Alcoholism interview, developed by the Collaborative Study on the Genetics of Alcoholism (Bucholz et al., 1994; Hesselbrock et al., 1999). These items corresponded to the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV); American Psychiatric Association, 1994 criteria of alcohol abuse and dependence. Antisocial behavior items were adapted from the Edinburgh Study of Youth Transitions and Crime (ESYTC) (Smith and McVie, 2003) and represented various domains of delinquent behaviors, such as theft, violence, and truancy. At ages 12, 15, and 17, the same computerized questionnaire protocol that was used for alcohol use was used to measure antisocial behavior during in-person clinic sessions. At age 13, measures of antisocial behavior were not available from the same computerized questionnaire, and we instead used antisocial behavior data collected by mailed questionnaire, which was administered when participants’ average age was 13.9 years. Some items were excluded from the analyses because
