Data were drawn from the Collaborative Study on the Genetics of Alcoholism (COGA) Prospective Study (Bucholz et al. 2017). COGA is a diverse, multi-site, multi-generational family-based study of genetic and environmental factors for alcohol use disorders (Begleiter et al. 1995; Reich et al. 1998). Alcohol-dependent probands were ascertained through alcohol treatment programs at seven U.S. sites. In addition, a group of community comparison families were recruited into the study. Beginning in 2004, a sample of adolescent and young adult offspring (ages 12–22) of prior adult COGA participants were recruited into the COGA Prospective Study to study the development of alcohol use disorders and related problems (Bucholz et al. 2017). Prospective Study participants were interviewed at enrollment and followed up at approximately biennial intervals. The Institutional Review Board at all sites approved this study, and written consent (and assent for adolescents) was obtained from all participants.
