The Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) interview and an adolescent version of the SSAGA (Bucholz et al., 1994) were administered to adults and individuals age 17 or under, respectively. An AD case was defined as an individual age 15 or older who met the DSM-IV criteria for AD, to exclude early onset AD, which may have different etiology (Dick et al., 2014). Control subjects were at least 21 years old and had consumed at least one full drink of alcohol in their lifetime, but who did not endorse more than one DSM-IV AD criterion. We set the minimum age as 21 to exclude individuals who had not have passed through the period of major risk for the onset of AD (Grant et al., 2004, Hingson et al., 2006). All others were not classified. Although these unclassified individuals were not used in any analysis related to DSM-IV AD, they were included in all other analysis (e.g. GWAS of SRE scores).
