Because of the relatively low power for heritability estimation for PTSD with our current samples, we decided to limit the number of genetic correlations tested to focus on three major adult psychiatric disorders (SCZ,16 BIP31 and MDD32) for which GWAS results from large studies are publicly available. As shown in the top (EA) portion of Table 1, PRS suggested overlap with both SCZ and BIP even after overly stringent (because of correlated tests) Bonferroni correction. Moreover, 58% (22/38) of PRS tests among EA individuals were nominally significant. For variance explained by discovery disorder P-value bins and associated statistics, see Supplementary Table S6. In contrast, PRS revealed no evidence of overlap with MDD, but this could be because of low power in both the MDD40 and the present PTSD analysis.41 This possibility is consistent with evidence of PTSD-MDD genetic overlap found with the more powerful (constrained) version of LDSC. Constrained LDSC results further supported the PRS finding of shared PTSD-SCZ genetic effects.
