Data were drawn from 5 cohorts: (a) a case-control (18) and (b) family GWAS (19;20) component of the Collaborative Study on the Genetics of Alcoholism (COGA; COGA-cc and COGA-f), (c) the Study of Addictions: Genes and Environment (SAGE)(21), (d) the Australian Alcohol (22), Nicotine Addiction Genetics (23), and Childhood Trauma (24) studies (OZALC+) and (e) the Comorbidity and Trauma Study (CATS)(25). Individual studies have been described in detail in related publications and in Supplemental Text. An outline of the samples used in this study is available in Table 2. As the overwhelming majority of the data were on individuals of European-Australian and European-American descent, discovery analyses were restricted to individuals of European descent. All subjects provided informed consent and protocols were approved by the institutional review boards overseeing the individual studies (see Supplemental text).
