The Collaborative Study on the Genetics of Alcoholism (COGA) is a large, multi-site study of 2,255 families affected with AUD, designed to identify and understand genetic factors involved in the predisposition to AUD and related disorders, as previously described (Agrawal et al., 2023; Begleiter, 1995; Dick et al., 2023). Probands along with all willing first-degree relatives were assessed; recruitment was extended to include additional relatives in families that contained 2 or more first degree relatives with alcohol dependence and community ascertained comparison families (N = 17,878). Participants 18 or older completed the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) which is a poly-diagnostic interview (Bucholz et al., 1994), and participants ages 12–17 completed an adolescent SSAGA. We currently have genome wide data on 12,145 individuals. Our final analytic sample consisted of 4,068 COGA participants with an alcohol dependence diagnosis (lifetime) and GWAS data (including 3,270 individuals of European-like and 798 individuals of African-like genetic similarity, see following section for discussion on assignment of genetic similarity).
