Blast effects on post-concussive and mental health outcomes: Data from Canadian Armed Forces breachers and snipers

Abstract

Introduction: In military personnel and Veterans returning from theatre, there is often comorbidity between blast-induced mild traumatic brain injury and psychiatric diagnoses. Therefore, researchers have focused on breachers and snipers to assess the effects of repetitive exposure to low-level blast in an operationally realistic, yet scientifically more controlled manner. Methods: Using a cross-sectional design, measures of neuropsychological functioning and mental health were administered to Canadian Armed Forces (CAF) breachers and snipers and sex- and age-matched CAF controls with no occupational history as breachers or snipers (n = 90). Results: Compared to controls, breachers and snipers scored higher on the Rivermead Post-Concussion Symptoms Questionnaire (RPQ). More cumulative exposure to explosives (in years) predicted RPQ symptom severity. In contrast, there was no difference between the two groups on mental health measures including Post-Traumatic Checklist-5 (PCL-5), Brief Symptom Inventory (BSI-18), or the emotional well-being sub-scale of the RAND SF-36. Forward stepwise regressions retained blast exposure in the final models to predict RPQ but not PCL-5, BSI-18, or RAND SF-36 scores. Discussion: Results suggest a history of repetitive exposure to blast is associated with greater levels of post-concussive symptoms in breachers and snipers, but not poorer mental health outcomes, despite the fact post-concussive symptoms and mental health outcomes are correlated. Therefore, it might be possible to dissociate post-concussive and mental health symptoms when the impact of exposure to repetitive low-level blast is assessed in the context of training and operations, rather than following warzone deployment involving primarily high-level blast exposure.