We report the basic descriptive statistics for the focal variables (i.e., means and standard deviations for continuous variables and distributions for binary or categorical variables). Pearson correlations were used to assess the intercorrelations between the substance use variables. Chi-square tests or t-tests were used to examine differences in alcohol use as a function of family history of problems with alcohol, other drugs, or depression/anxiety. Pearson correlations were used to assess the associations between the alcohol variables, mental health outcomes, and other related risk and protective factors. We also ran a series of chi-squared tests, t-tests, and regression to determine whether there were systematic differences in participation in the various components of the project (DNA collection, follow-up). All analyses were run in SPSS version 20 (Armonk, New York).
