J Neurotrauma. 2023 Dec 20. doi: 10.1089/neu.2023.0381. Online ahead of print.

ABSTRACT

The chronic mental health consequences of mild traumatic brain injury (TBI) are a leading cause of disability. This is surprising due to the expectation of significant recovery after mild TBI, suggesting other injury-related factors may contribute to long-term adverse outcomes. The objective of this study was to determine how number of prior injuries, gender, and environment/context of injury may contribute to depressive symptoms after mild TBI among deployed US Service Members and Veterans (SMVs). Data from the Long-term Impact of Military-relevant Brain Injury Consortium Prospective Longitudinal Study was used to assess TBI injury characteristics and depression scores previously measured on the Patient Health Questionnaire-9 (PHQ-9) among a sample of 1,456 deployed SMVs. Clinical diagnosis of mild TBI was defined via a multi-step process centered on a structured face-to-face interview. Logistic and linear regressions stratified by gender and environment of injury were used to model depressive symptoms controlling for sociodemographic and combat deployment covariates. Relative to controls with no history of mild TBI (N=280), the odds ratios (OR) for moderate/severe depression (PHQ-9≥10) were higher for SMVs with one mild TBI (N=358) OR: 1.62 (95% CI [1.09 – 2.40, p=0.016] and two or more mild TBIs (n = 818) OR: 1.84 [95% CI 1.31 – 2.59], p<0.001). Risk differences across groups were assessed in stratified linear models, which found that depression symptoms were elevated given history of multiple mild TBIs compared to single mild TBIs (p<0.001). Combat deployment-related injuries were also associated with higher depression scores than injuries occurring in noncombat or civilian settings (p<0.001). Increased rates of depression after mild TBI persisted in the absence of post-traumatic stress disorder. Both men and women SMVs separately exhibited significantly increased depressive symptom scores given combat-related mild TBI. These results suggest that contextual information, gender, and prior injury history may influence long-term mental health outcomes among SMVs with mild TBI exposure.

PMID:38117134 | DOI:10.1089/neu.2023.0381