Semi-structured psychiatric diagnostic interviews were completed in-person by cases and neighborhood controls; ATR controls had completed telephone interviews previously. Diagnostic sections on illicit drug and alcohol dependence were modified from the Semi-Structured Assessment for the Genetics of Alcoholism - Australia (SSAGA-OZ);29 the nicotine dependence section was modified from the Nicotine Addiction Genetics Study assessment.30 The assessments provided DSM-IV lifetime diagnoses of opioid, cannabis, sedative, stimulant, cocaine, and alcohol abuse and dependence, as well as nicotine dependence. Similar diagnoses were obtained for Comorbidity and Trauma Study (CATS) pilot project participants via the World Health Organization Composite International Diagnostic Interview.31
