In conclusion, polygenic risk of PTSD, derived from the PGC-PTSD most recent GWAS on PTSD diagnosis, was associated with increased likelihood of DSM-IV PTSD, and DSM-IV alcohol and cocaine dependence diagnoses in an independent sample of individuals densely affected with alcohol use disorders. Further, individuals with higher polygenic risk for PTSD and a lifetime alcohol dependence diagnosis were more likely to have PTSD than those without alcohol dependence. These results further support the importance of examining substance use problems, specifically alcohol dependence, and PTSD together when investigating genetic influence on these disorders.
