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. Controls were defined as individuals who had been exposed to alcohol and nicotine (and possibly to other drugs), but had never become dependent on these substances. Additionally, controls were also screened to exclude individuals with major axis I disorders, including schizophrenia, mood disorders, and anxiety disorders. The Australian subjects included twins and their parents, siblings, spouses, children and other family members. The index cases reported a history of alcohol dependence and nicotine dependence (DSM-IV). More detailed demographic information is available elsewhere (Edenberg et al., 2005; Bierut et al., 2010; Edenberg et al., 2010; Heath et al., 2011). The European-American discovery cohort and the African-American replication cohort were genotyped on the Illumina Human 1M beadchip and the Australian cohort was genotyped on the Illumina CNV370v1 beadchip.
