AOO curves were generated using the actuarial method (Halli et al., 1992). Tetrachoric factor analysis (principal axis method) with promax rotation was used to examine bivariate comorbidity. Temporal unfolding was studied by examining predictive associations between temporally primary disorders (based on retrospective AOO reports) and first onset of later disorders with multivariate discrete-time survival models using a person-year dataset (Willett & Singer, 1993). The details of this modeling procedure, which we have used extensively in previous NCS reports, are presented elsewhere (Kessler et al., 2005). Each model predicted first onset of one disorder from information about prior lifetime occurrence of the other 14 disorders controlling basic socio-demographic variables (sex, race/ethnicity [Non-Hispanic White, Non-Hispanic Black, Hispanic, Other], region of the country [Northeast, Midwest, South, West], urbanicity [Major Metropolitan Area, other urbanized area, rural area], parent education [less than high school, high school, some college, college graduate, coded for the parent with the higher level of education], number of biological parents with whom the adolescent lives [0-2], birth order [only child, oldest, youngest, other], number of siblings, and age).
