The three PTSD phenotypic subdomains loaded onto a single latent common factor (Supplementary Fig. 2). There were no significant differences in loading values between these PTSD subdomains, suggesting roughly equal contribution of all three to the common factor (comparative fit index (CFI) = 0.996). Next, we included PTSD genetic and phenotypic correlates from internalizing disorders – anxiety, neuroticism, and major depressive disorder (all from PGC). Genomic exploratory factor analysis (EFA) identified a two-factor model as best suited to represent the six phenotypes (i.e., PTSD subdomains and the three internalizing measures). In genomic confirmatory factor analysis (CFA) of the two-factor model, PTSD subdomains independently loaded onto factor 1 while the PTSD correlates loaded onto a second factor (CFI = 0.999) (Fig. 6). The PTSD subdomain hyperarousal loads onto both factors (loading onto factor 1 = 0.90 ± 0.05; loading onto factor 2 = 0.10 ± 0.04; correlation between factors 1 and 2 = 0.72 ± 0.03), indicating that this subdomain has a genetic correlation with the internalizing psychopathologies that is not shared by the other PTSD subdomains.
