The impact of head injury mechanism on mental health symptoms in veterans: do number and type of exposures matter?

This study examined the association between screening results for mental health problems and the number and type of head injuries in 1,082 Iraq and Afghanistan War veterans who received population-based screening for traumatic brain injury at a Veterans Administration health care facility. Nearly one third of all veterans reported multiple types of head injuries (median = 1 among those with any head injury, range = 1-6 types of head injury). Veterans reporting multiple head injury mechanisms had 6 times the odds of screening positive for posttraumatic stress disorder (PTSD), adjusted odds ratio (OR) = 6.15, 95% confidence interval (CI) [4.4, 8.7], p < .001, over 4 times the odds of screening positive for depression, adjusted OR = 4.09, 95% CI [2.8, 5.9], p < .001, and about twice the odds of screening positive for alcohol misuse, adjusted OR = 1.64, 95% CI [1.19, 2.3], p = .003, compared to those without head injuries. Veterans reporting a blast plus another head injury mechanism had higher odds of screening positive for all mental health outcomes than any other group (e.g., compared to no head injury group): PTSD, adjusted OR = 6.52, 95% CI [4.6, 9.3], p < .001; depression, adjusted OR = 4.42, 95% CI [3.0, 6.4], p < .001; alcohol misuse, adjusted OR =1.59, 95% CI [1.14, 2.2], p = .006. Given their association with a variety of mental health outcomes, number and type of head injury mechanism should be considered as part of any postdeployment evaluation.