We opted to examine subdiagnostic levels of alcohol dependence and conduct disorder in order to assess risk of early sexual debut among individuals who exhibited some of these problems without necessarily meeting full diagnostic criteria. The age at which the earliest symptom of alcohol dependence first occurred was treated as a time dependent covariate, and counted only if it occurred prior to age of first sexual intercourse. Age at which the earliest conduct disorder symptom first occurred was also considered as a time dependent covariate, and counted only if the symptom occurred prior to age of first sexual intercourse. All other independent variables were treated as time independent covariates. p-values were estimated by Wald's tests.
