liability-threshold and burden or risk variants in females) could not be explicitly tested due to the still lower statistical power in the female sample, as the sample was predominately male (93%). Present study analyses did include sex-stratified PTSD subsamples, supported by previous findings of sex differences in PTSD heritability (Duncan et al., 2018; Nievergelt et al., 2019). Further, given previous findings of differences in heritability estimates within male PTSD subsamples (Nievergelt et al., 2019), we examined UKB male PTSD results separate from the PTSD-PGC1.5 male PTSD results. We found a moderate genetic correlation between combined AD and PTSD in females (rg = 0.34, SE = .14) as well as between combined AD and the male sub-sample that demonstrated a significant heritability estimate (UKB sample; rg = 0.51, SE = .24). While study findings suggest a fairly comparable PTSD-AD genetic correlation in these subsamples, considerable additional research will be needed to examine the nuances of sex differences in PTSD-AD/AUD shared genetic risk; at present, it remains unknown whether sex differences in the genetic correlation are to be expected. Further, the small, existing literature is mixed with regard to sex differences in the prevalence of comorbid PTSD-AUD (e.g., Kozaric-Kovacic et al., 2000,
