Table 1 details the phenotypic correlations across the different measures of AC and problem drinking. Polychoric correlations were computed on only 1 twin from each pair, chosen randomly. Table 2 shows the MZ and DZ twin correlations for each of the measures. The results of the series of models fit are shown in Table 3. We initially fit a full Cholesky model including full A, C, and E matrices separately for each sex (AIC = 5967.906, df = 16618; Model I in Table 3). Next, we tested a model in which we constrained all parameters to be equal in men and women (Model II). The AIC decreased and the chi-squared change was nonsignificant for the change in degrees of freedom, indicating that the more parsimonious model constraining men and women to be equal provided a better fit. We next tested a model including full A and E matrices and dropping the full C matrix representative of all shared environmental influences (Model III). The AIC decreased and the chi-squared change was nonsignificant for the change in degrees of freedom, indicating that
