Approximately one-third of individuals with PTSD have co-occurring alcohol dependence [5]. In addition, individuals with a family history of alcohol dependence are at increased risk of experiencing a traumatic event and developing PTSD [13–16], potentially due to shared psychosocial risk factors (i.e., adverse childhood experiences) and/or the shared genetic liability of PTSD and alcohol dependence and other substance use disorders [6, 8, 17]. Using GWAS data, Sheerin et al. (2020) confirmed a significant genetic correlation between PTSD and alcohol dependence (rG = 0.35) [8], first observed in twin studies [6, 8, 17–19]. Given sex differences in prevalence of PTSD [4, 20] and sex differences in the heritability of PTSD [9, 21, 22], Sheerin and colleagues conducted sex-stratified analyses, and found a significant genetic correlation between PTSD and alcohol dependence in females (rG = 0.34), but not in males (rG = 0.14) [8].
