The sample used for this study was the Study of Addiction: Genes and Environment (SAGE: (Bierut et al., 2010)) which drew data from three independent family-based studies to create a sample of unrelated DSM-IV alcohol dependent cases and alcohol exposed controls. The parent studies were family-based and ascertained for alcohol dependence (Collaborative Study of the Genetics of Alcoholism, COGA, (Begleiter et al., 1995)), nicotine dependence (Collaborative Study of the Genetics of Nicotine Dependence, COGEND, (Bierut et al., 2007)) and cocaine dependence (Family Study of Cocaine Dependence, FSCD (Bierut, Strickland, Thompson, Afful, & Cottler, 2008). The SAGE series consisted of 1899 unrelated DSM-IV alcohol dependent cases and 1938 unrelated alcohol exposed (drank at least one drink during the lifetime) controls.
