This GWAS of PTSD in COGA families, many of which are densely affected with alcohol use disorders, yielded no genome-wide significant loci. However, associations of polygenic risk for PTSD were observed with DSM-IV PTSD as well as alcohol and cocaine dependence using PRS calculated from PGC-PTSD Freeze 2 data [9]. Further, individuals with increased polygenic risk for PTSD and a lifetime alcohol or cocaine dependence diagnosis were more likely to have PTSD than those without alcohol or cocaine dependence. The main effects observed for the PGC-PTSD PRS were not seen when investigating the same associations using PRS calculated from the MVP GWAS on PTSD diagnosis.
