We next characterized the genetic overlap between MVP-EXT and suicide related phenotypes. First, we estimated the genetic correlations between MVP-EXT and both suicide attempt (SUI)61 and suicidal ideation (IDE)62. Figure 2 (Panel A) presents genetic correlation estimates for the EUR-like and AFR-like results side by side. Genetic correlations with SUI were strong for both the EUR-like (rG = 0.67, 95% CI = 0.60, 0.91) and AFR-like (rG = 0.74, 95% CI = 0.42, 0.81) participants. Genetic correlations with IDE were weak, but significant in the EUR-like (rG = 0.12, 95% CI = 0.08, 0.17) veterans and null for AFR-like (rG = −0.01, 95% CI = −0.20, 0.18) veterans. The results from MiXeR indicated that MVP-EXT shared ~77% of its influential variants with suicide attempt. Within this shared component, the variants that influence both MVP-EXT and suicide attempt had high sign concordance between SNPs (79%, SE = 0.03), supporting a model in which externalizing and suicide attempt were distinct traits with substantial polygenic overlap (full results in Supplemental Table 9).
