The Study of Addiction: Genes and Environment (SAGE) [32] is a case-control sample of unrelated individuals over-selected for substance dependence. Specifically, the SAGE sample was derived from three primary studies of alcohol, nicotine, and cocaine dependence, such that the final sample included approximately 50% alcohol dependent cases and 50% non-dependent controls. All controls were community-ascertained and did not meet criteria for dependence on any substance. Alcohol dependent cases drawn from the primary study of nicotine dependence were community-ascertained, while alcohol dependent cases drawn from the primary studies of alcohol and cocaine dependence were clinically ascertained. All alcohol dependent cases qualified for inclusion in SAGE regardless of dependence status on other substances. The SAGE study (N=4121) is 54.3% female, 67.3% Caucasian and 32.5% African American, with 3.4% participants reporting Hispanic ancestry. The SAGE sample has a mean age of 39.03 (SD = 9.10, range = 18–77), with 47.2% participants meeting DSM-IV criteria for alcohol dependence, 18.3% meeting criteria for marijuana dependence, and 27.4% meeting criteria for cocaine dependence. All data from SAGE utilized for the current study are publicly available via the database of Genotypes and Phenotypes (dbGaP; phs000092.v1.p1).
