The European-American discovery cohort and the African-American replication cohort came from the dataset of the Study of Addiction - Genetics and Environment (SAGE) (dbGaP study accession phs000092.v1.p1) (Bierut et al., 2010), and the Australian replication cohort came from the dataset of the Australian twin-family study of alcohol use disorder (OZ-ALC) (dbGaP study accession phs000181.v1.p1) (Lind et al., 2010; Heath et al., 2011). (All subjects with alcohol and nicotine co-dependence in another dataset of the Collaborative Study on the Genetics of Alcoholism (COGA) (dbGaP: phs000125.v1.p1) (Edenberg et al., 2010) have been included in this SAGE dataset). These datasets were originally collected to study alcohol dependence alone. SAGE subjects were recruited from 8 different study sites in 7 states and the District of Columbia; the majority of subjects were recruited in Missouri (Bierut et al., 2010). All subjects were interviewed using the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) (Bucholz et al., 1994). Affected subjects met lifetime DSM-IV criteria for both alcohol and nicotine dependence (American Psychiatric Association, 1994). Affected subjects were excluded if they had schizophrenia or other psychotic illnesses.
