Six sites participating in the Collaborative Study on the Genetics of Alcoholism (COGA; Begleiter et al., 1995; Foroud et al., 2000a) recruited alcohol dependent probands from inpatient and outpatient facilities. The probands and their family members were administered a poly-diagnostic interview, the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA; Bucholz et al., 1994; Hesselbrock et al., 1999). Individuals 18 years of age or younger were administered an adolescent version of the SSAGA. Institutional review boards at all sites approved the study. The present COGA sample consisted of 1788 regular drinkers subjects of European descent from 118 extended families. Further details about the complete cohort are described elsewhere (Kang et al., 2012; Wang et al., 2013).
