Within-individual cross-trait tetrachoric correlations for the 4 phenotypes are reported in Table 3. All correlations involving low-risk trauma were of modest magnitude; the somewhat counterintuitive negative correlation (r=−0.19) observed with PTSD can be attributed to classifying non–trauma-exposed individuals as missing for the disorder. In contrast, the correlations between high-risk trauma and PTSD and between high-risk trauma and MDD were 0.65 and 0.38, respectively.
