The Collaborative Study on the Genetics of Alcoholism (COGA) is a large, multi-site study of 17,854 participants from 2255 families, many of which are densely affected with AUD, designed to identify and understand genetic factors involved in the predisposition to develop alcohol use disorder and related disorders, as previously described [32, 33]. Beginning in 1990, participants were administered a comprehensive battery that included clinical and neurophysiological assessments, and DNA samples for genomic analysis (see [32] for description of recruitment and assessment procedures). Clinical assessments of substance use and psychiatric disorders were obtained using the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) developed in COGA, which is a reliable and valid poly-diagnostic interview [34, 35]. A developmentally appropriate version of the SSAGA was administered to those under age 18 [36]. Starting in 1997, assessments for trauma exposure were added to the SSAGA; participants who reported a qualifying trauma were then queried about symptoms of PTSD that were required for a DSM-IV diagnosis (Diagnostic and Statistical Manual of Mental Disorders-IV) [35, 37]. For the purpose of this study, data were included
