Because we have previously found DSM-III-R diagnoses of major depression (lifetime), conduct disorder (before age 16), and posttraumatic stress disorder (PTSD, lifetime), as well as service in Southeast Asia, to be significant covariates when examining the relationship between early substance use and adult drug dependence (Grant et al., 2006, 2010), these variables were included in all adjusted models. All DSM-III-R diagnoses were assessed in the 1992 telephone diagnostic interview; service in Southeast Asia was assessed in the 1987 mailed questionnaire.
