note that developmental analyses of alcohol effects need to control for these comorbidities. Although rates of alcohol initiation and use in adolescence are comparable for boys and girls (Johnston et al., 2010), rates of heavy drinking and adverse consequences tend to be higher among males, particularly in late adolescence and early adulthood (e.g., Ellickson, Tucker, Klein, & McGuigan, 2001). Thus, gender was included as a covariate in the analyses. Gender moderation of the hypothesized longitudinal relationships under investigation also was explored. Finally, because it has been shown to be associated with attrition in the current longitudinal study, a measure of parent educational attainment also was included as a covariate.
