Lifetime indices of psychiatric comorbidity, early regular alcohol and cigarette use, and Southeast Asia service were included as covariates in analyses. DSM-III-R depression (lifetime), conduct disorder (before age 16), and Post-Traumatic Stress Disorder (PTSD, lifetime) were assessed in the 1992 telephone diagnostic interview. Regular alcohol use was assessed in the 1992 telephone interview through a question that asked when they had “first had any wine, beer, or other alcohol at least once a month for 6 months or more”. The 25% of respondents (29% of regular drinkers) who indicated they began drinking on at least a monthly basis before age 18 were classified as early regular alcohol users, with those who never drank regularly coded as “no” for early regular alcohol use. Based on information from the 1987 self-report questionnaire, 66% of respondents had smoked 100+ cigarettes lifetime. Respondents were classified as early nicotine users if they reported smoking at least 100 cigarettes lifetime before age 18. Using this criterion, 28% of respondents were early regular smokers (46% of those who had smoked 100+ cigarettes lifetime). In the 1987 self-report
