Both co-twins in this sub-sample were interviewed at ages of 14 and 22 using the Semi-Structured Assessment for the Genetics of Alcoholism (Bucholz et al., 1994), a widely-used, reliable instrument providing detailed assessments of tobacco use, SRB, and lifetime diagnoses (DSM-IIIR, DSM-IV) for several disorders, including alcohol dependence and major depressive disorder (MDD). The twins at age 14 were administered the adolescent version of SSAGA (C-SSAGA-A) whereas the adult SSAGA was administered at age 22. All interviewers were trained by personnel from Indiana University's Institute of Psychiatric Research using standard COGA-interview training procedures (Edenberg 2002).
