Details on the Yale-Penn sample have been published previously24, 27, 28. Briefly, adults with a history of dependence on alcohol, opioids, or cocaine and controls were recruited at five sites in the Eastern United States, primarily via community advertisements and word of mouth, as part of ongoing studies of drug and alcohol dependence genetics. The sample consisted of small nuclear families with affected and unaffected members (originally collected for linkage studies), and unrelated cases and controls. Exclusion criteria included a history of psychotic disorders (schizophrenia, bipolar disorder), serious head injury, or inability to read English at a sixth-grade level. Subjects gave written informed consent as approved by the Institutional Review Board (IRB) at each site, and certificates of confidentiality were obtained from the National Institute on Drug Abuse and the National Institute on Alcohol Abuse and Alcoholism. In-person interviews were conducted by trained interviewers using the Semi-Structured Assessment for Drug Dependence and Alcoholism (SSADDA), which is a comprehensive polydiagnostic instrument that yields reliable information on major DSM-IV diagnoses and diagnostic criteria (available at https://nidagenetics.org/filebrowser/download/3765).29, 30 The SSADDA covers psychiatric and substance use disorders, as well as social and medical history and demographic information.
