All subjects participated in an interview developed specifically for COGA, the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA; Bucholz et al., 1994; Bucholz et al., 1995; Hesselbrock, Easton, Bucholz, Schuckit, & Hesselbrock, 1999). The SSAGA is a comprehensive psychiatric interview that was designed to accommodate several diagnostic systems, including DSM-III-R (American Psychiatric Association, 1987), DSM-IV (American Psychiatric Association, 1994), ICD-10 (World Health Organization, 1993), and Feighner alcohol diagnostic criteria (Feighner et al., 1972). It includes assessments for alcohol and drug use and dependence, major depression, panic disorder, posttraumatic stress disorder, conduct disorder, and antisocial personality disorder. Because DSM-IV criteria were not yet published at the time of the first stage of data collection, and because we combined data from phases 1 and 2 for this analysis, we based our dichotomous alcohol dependence, psychiatric disorder, and drug dependence variables on DSM-III-R criteria. For alcohol diagnostic criteria (Table 2), we utilized DSM-III-R and Feighner criteria. All demographic data were based on the most recent interview, with 59% of participants having data from Stage 2 and 41% having data from Stage 1 only.
