Predictors of Current DSM-5 PTSD Diagnosis and Symptom Severity Among Deployed Veterans: Significance of Predisposition, Stress Exposure, and Genetics

Previously we reported a genetic risk score significantly improved PTSD prediction among a trauma-exposed civilian population. In the current study, we sought to assess this prediction among a trauma-exposed military population. We examined current PTSD diagnosis and PTSD symptom severity among a random sample of 1042 community-based US military veterans. Main effects and interaction effects were assessed for PTSD genetic risk by trauma exposure using cross-product terms for PTSD x trauma exposures, including combat, lifetime trauma, and adverse childhood exposures. The PTSD risk variants studied were within genetic loci previously associated with PTSD, including , , , and genetic variants, which were used to calculate a total PTSD genetic risk score (range=0-8, mean=3.6, SD=1.4). Based on DSM-5 PTSD criteria, 7.1% of veterans (95% CI=5.6-8.8) met criteria for current PTSD. The PTSD genetic risk count was significantly higher among PTSD cases vs non-cases (3.92 vs 3.55, p=0.027). Since the PTSD genetic risk score was not significant in the PTSD diagnosis model, we assessed this association using PTSD symptom severity. Because these symptom data were skewed (mean=9.54, SD=12.71, range=0-76), we used negative binomial regression to assess this outcome. This symptom model included a PTSD genetic risk score, demographic factors, trauma exposures, current insomnia, current depression, concussion history, and attention-deficit disorder, expressed as incident rate ratios (IRR), which is an estimate of one-unit increase in PTSD severity, given other variables are held constant. Variables in the final model included age and sex (both p