most of a subject's best friends drank, and if the subject smoked a cigarette before initiating drinking) and eight scale scores from the commonly used Achenbach Youth Self Report (Achenbach & Rescorla, 2001) to predict the onset of alcohol initiation in an independent sample of 820 adolescent COGA subjects (∼60% had not initiated drinking) utilizing the Cox proportional hazards models. Four of these Achenbach Youth Self Report (YSR) scales were hypothesized to be protective and decrease the risk for drinking initiation (positive qualities, activities competence, social competence, and school competence), and four were predicted to be harmful and increase the risk for alcohol initiation in this young cohort (externalizing, attentional, social problems, and internalizing scores). The most parsimonious model included the following: 1) most best friends drank (MBFD), 2) high-risk AD family membership, 3) number of CD symptoms, 4) YSR externalizing score (a non-diagnostic 32-item scale of a wide array of problematic behavior defined as being aggressive, hostile, destructive, defiant in nature, and at odds with accepted societal norms), and 5) YSR social problems score (a non-diagnostic 11-item scale that assesses difficulties with friends and peers).
