The Collaborative Study on the Genetics of Alcoholism (COGA) is a family-based study with deep and repeated phenotyping of substance use disorders (SUDs), comorbid psychiatric disorders, and related traits (including polygenic liability and electrophysiological markers) designed to examine the genetic substrates of AUD and its development across the life span.19 AUD probands were recruited primarily from treatment facilities across 7 US collection sites. Families of probands that included 3 or more individuals with alcohol dependence were also recruited and included members with and without alcohol dependence. Comparison families (ie, without ascertainment for alcohol dependence or exclusion for it) were also selected from a variety of community sources.20 The institutional review boards at all 7 sites approved this study, and written consent was obtained from all participants. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines for cohort studies. Data were restricted to alcohol-exposed individuals (ie, endorsing lifetime use of any alcohol) from 2 COGA subsamples: (1) a cross-sectional cohort of 13 110 individuals from 2234 families assessed from 1991 to 2005, and (2) a longitudinal cohort comprising 2818 offspring of individuals from the cross-sectional cohort, born after 1981 and assessed from 2004 to 2019.20
