FSCD was designed as a genetic and environmental study of drug dependence with a focus on cocaine dependence. Cocaine-dependent subjects were recruited systematically from chemical dependency treatment units in the greater St. Louis, MO, metropolitan area (12). Community-based control subjects were identified through the Missouri Family Registry and matched by age, race, gender, and residential zip code. The community-based control subjects had used alcohol, but never met criteria for any alcohol, nicotine, or other drug dependence. The present study includes 1171 unrelated genotyped subjects from FSCD.
