Figure 1 illustrates the path diagram of the AE Cholesky model. A1 and E1 represent the additive genetic and non-shared environmental variance, respectively, that is shared by all three endophenotypes and EXT. A2 and E2 are the variances shared by TF-PC1, Beta, and EXT, independent of that shared with P3. A3 and E3 are the variances shared by Beta and EXT, independent of that shared with P3 and TF-PC1. A4 and E4 are the variances unique to EXT. Shown are the standardized path coefficients, which, when squared, represent the proportion of variance accounted for by the respective path. To assess the significance of each path, we constrained it equal to 0 and assessed fit by means of likelihood-ratio tests, AIC, and DIC. Significant likelihood-ratio tests and larger values of the information-theoretic fit statistics indicate significance of the path being tested. Results of these tests are presented in Table 4 for the genetic factors. The three fit statistics were consistent in showing a significant effect of A1 on the three endophenotypes, indicating shared genetic variance among them, for both males and
