Background: Headache is often associated with physical trauma and psychological stress. The aim of this study is to evaluate the impact of headache on personnel deployed in war zones and to identify factors associated with return to duty (RTD).

Methods: Outcome data were prospectively collected on 985 personnel medically evacuated out of Operations Iraqi and Enduring Freedom for a primary diagnosis of headache between 2004 and 2009. Electronic medical records were reviewed to examine clinical and treatment patterns and the effect that myriad factors had on RTD.

Results: 33.6% of evacuees returned to duty. The most common headaches were post-concussion (34.1%) and migraine (30.0%). Headaches typically associated with trauma such as post-concussion (18.7%), occipital neuralgia (23.1%), and cervicogenic headache (29.7%) had the lowest RTD rates, whereas tension headache (49.6%) was associated with the best outcome. Other variables associated with negative outcome included presence of aura (OR 0.51, 95% CI 0.30–0.88; p = 0.02), traumatic brain injury (OR 0.50, 95% CI 0.29–0.87; p = 0.01), opioid (OR 0.41, 95% CI 0.26–0.63; p < 0.001), and beta-blocker (OR 0.26, 95% CI 0.12–0.61; p = 0.002) use, and co-existing psychopathology (p < 0.001 in univariable analysis).

Conclusion: Headaches represent a significant cause of unit attrition in personnel deployed in military operations, with physical trauma and co-existing psychopathology associated with poorer outcomes.