The sample comprised of a total of 3,143 subjects for gene-disease association analysis, including 818 European-American (EA) cases with alcohol and nicotine co-dependence, 1,396 EA controls, 449 African-American (AA) cases and 480 AA controls. This sample was extracted from SAGE (dbGaP study accession phs000092.v1.p1)[Bierut et al., 2010]. 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[American Psychiatric Association 1994] both for alcohol dependence and nicotine dependence, and were excluded if they had schizophrenia or other psychotic illnesses. Controls were defined as individuals who had been exposed to alcohol and nicotine in sufficient amounts for a sufficient time, but had never become dependent on or abused alcohol, nicotine or other illicit substances (see Supplemental Table S1). Additionally, controls were also screened to exclude individuals with major axis I disorders, including schizophrenia, mood disorders, and anxiety disorders. More demographic data
