While recently published GWAS [9, 21, 22] have begun to identify genomic markers of PTSD in civilian and military populations, these studies have yet to examine the genetics of PTSD while considering co-occurring influences of alcohol dependence. Further, whether the shared risk between PTSD and alcohol use disorders extends to other substance use disorders is less clear. While recent studies have suggested that genetic risk is shared across a range of externalizing disorders (including alcohol, cannabis, and nicotine use disorders) [12], prior research has demonstrated that some risk factors may be unique to each substance use disorder [23].
