Association between combat stress and post-concussive symptom reporting in OEF/OIF service members with mild traumatic brain injuries

Objective: The relationship between combat stress and post-concussive symptoms in service members with mild traumatic brain injuries (mTBI) is poorly understood. It was hypothesized that the co-occurrence of combat stress would have a significant effect on the severity of post-concussive complaints, specifically on emotional and cognitive symptoms. Methods: Four hundred and seventy-two combat-deployed service members with mTBI completed self-report inventories of post-traumatic stress and post-concussive symptoms. Two groups were formed based on post-traumatic stress symptoms (High Combat Stress and Low Combat Stress). Results: A 3-8-fold increase in post-concussive symptoms was observed when comparing the High and Low Combat Stress Groups. Elevations in post-concussive symptom reporting were not limited to emotional and/or cognitive symptoms, but rather were inclusive of all measured post-concussive symptoms. Conclusions: The findings of the present study suggest that non-brain injury-related factors, such as high-levels of combat stress, may impact post-concussive symptom reporting in this population, further confounding the accuracy of the post-concussion syndrome (PCS) diagnosis. Considerable caution should be exercised in making the diagnosis of PCS in concussed service members with co-occurring combat-stress disorders.