Subjects were recruited for participation in studies of the genetics of cocaine, opioid, and alcohol dependence from the communities around five sites in the United States: the University of Connecticut Health Center (UConn), Yale University School of Medicine (Yale), the Medical University of South Carolina (MUSC), the University of Pennsylvania (UPENN) and McLean Hospital (McLean). Subjects were interviewed using an electronic version of the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA) instrument (Gelernter et al., 2005; Pierucci-Lagha et al., 2005). Most controls were recruited at the same recruitment sites (excluding McLean) and were screened to exclude those with a diagnosis of DSM-IV substance abuse or dependence, and a major Axis I psychiatric disorders. The study protocol was approved by the institutional review board at each site. A complete description of the study was provided to all subjects, who then gave written informed consent. Subjects were paid for their study participation.
