the best-fitting common pathway model differed across men and women due to differences in substance-specific estimates. As mentioned above, however, this study differed with respect to phenotype definition and sample characteristics. Also, strong inferences regarding sex differences in CPM structure should not be drawn from the present report, as this model did not fit significantly better than the IPM. Prior analyses of the multivariate structure of substance abuse/dependence in adults (Kendler et al., 2003; Tsuang et al., 1998; Xian et al., 2008) have largely been conducted with male-only or female-only samples. Future multivariate studies that (a) employ both men and women and (b) examine substance use disorder in relation to other phenotypes will help clarify the nature of sex differences in polysubstance use across various stages of involvement.
