Association of anger and aggression with post-traumatic stress disorder and mild traumatic brain injury in U.S. service members

Abstract: INTRODUCTION: Anger and aggression are strongly associated with PTSD. Less well established is their association with mild traumatic brain injury (mTBI) and how specific types of anger-based aggressive behaviors manifest in the context of PTSD, mTBI, and comorbid mTBI/PTSD. MATERIALS AND METHODS: We conducted secondary analyses of data from the 2018 DoD Health Related Behaviors Survey. Respondents included 17,065 active component service members (SMs) who screened positive for mTBI sustained within the previous 12 months, PTSD, comorbid mTBI/PTSD, or neither (Control group). We examined the prevalence and association of 4 angry/aggressive behaviors within the 4 groups using a multivariate multinomial regression model. Behaviors included a 30-day frequency of yelling at someone, object-directed aggression, threatening someone with physical violence, or hitting someone. We calculated odds ratios and conditional probabilities, adjusting for demographics and combat deployment history. The RAND Corporation conducted the Health Related Behaviors Survey and obtained necessary Institutional Review Board approval and second-level review by the DoD. RESULTS: Respondents with a positive screen for either mTBI or PTSD, or both, had greater odds of reporting angry/aggressive behavior in the last month than those without a positive screen. PTSD (alone or comorbid with mTBI) had the strongest association with recurrent yelling (adjusted odds ratio [aOR]=4.76, 95% CI: 3.97, 5.72). The Comorbid group had the strongest association with recurrent object-directed aggression (aOR=7.64, 95% CI: 4.94, 11.84), an effect that was suggestive of an approximately additive contribution of mTBI and PTSD (aOR=3.73, 95% CI: 2.86, 4.87). CONCLUSIONS: This work provides evidence linking recent mTBI to increased anger/aggression and shows that mTBI can be as strongly associated as PTSD with physical aggression. Because of potentially severe ramifications of unchecked anger/aggression, clinicians treating SMs with mTBI and/or PTSD should consider these different behavioral indications, especially in comorbid cases.