Psychological trauma and the genetic overlap between posttraumatic stress disorder and major depressive disorder

Abstract Background Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are commonly reported co-occurring mental health consequences following psychological trauma exposure. The disorders have high genetic overlap. We investigated whether the genetics of PTSD were associated with reported trauma in individuals with MDD. Since trauma is associated with recurrent MDD, we also investigated whether the genetics of PTSD were associated with episode recurrence. Methods Genetic correlations were estimated between PTSD and MDD in the presence and MDD in the absence of reported exposure to psychological trauma, and recurrent and single-episode MDD, based on genetic data from UK Biobank Mental Health Questionnaire respondents (N=157,358). Genetic correlations were replicated using PTSD data from the Psychiatric Genomics Consortium and Million Veteran Program. Polygenic risk scores were generated to investigate whether individuals with MDD who have higher genetic risk for PTSD were more likely to report psychological trauma than those with lower genetic risk. Results Individuals with MDD with a higher genetic risk for PTSD were significantly more likely to report exposure to psychological trauma than those with lower risk [OR=1.06 (1.03-1.09) Empricial p 167, p Conclusions Genetic risk for PTSD in individuals with MDD may influence the way in which traumatic life events are perceived, responded to and reported.