The Impact of Lifetime Traumatic Brain Injury (TBI) on Mental Health Symptoms among Service Members in Interdisciplinary TBI Programs.

Introduction: Traumatic brain injury (TBI) is highly prevalent among active duty service members (ADSMs) and imposes a significant health burden, particularly on mental health (e.g., post-traumatic stress disorder [PTSD] and depressive symptoms). Little is known about how TBI setting characteristics impact PTSD and depressive symptom expression in service members undergoing interdisciplinary TBI care.

Materials And Methods: The study included 455 patients enrolled in interdisciplinary, outpatient TBI programs within the military health system. Using Poisson regression with robust error variance, TBI injury setting characteristics (i.e., before military service, during military training, and during noncombat/combat deployment) were evaluated against clinically-elevated PTSD (PTSD Checklist, DSM-5 score ≥ 33) and depressive (Patient Health Questionnaire-8 score ≥ 15) symptoms.

Results: In adjusted models, TBI sustained before military service was associated with less likelihood for clinically-elevated PTSD symptoms at pretreatment (prevalence ratio [PR] = 0.76, confidence interval [CI] = 0.60-0.96) and post-treatment (PR = 0.67, CI = 0.52-0.87). TBI sustained during combat deployment, however, resulted in the greatest impact on clinically-elevated pretreatment PTSD (PR = 1.49, CI = 1.16-1.91) and depressive (PR = 1.47, CI = 1.06-2.03) symptoms. Null results were found between military training/noncombat deployment and mental health symptoms. Regardless of the TBI setting, following TBI treatment, there remained 37.5% (n = 180) and 24.8% (n = 108) with clinically-elevated PTSD and depressive symptoms, respectively.

Conclusions: There was a differential impact of TBI settings, particularly between TBI sustained before military service and that from combat deployment among ADSMs enrolled in outpatient TBI programs. This may be indicative of differences in the characteristics of these environments (e.g., injury severity) or the impact of such an event during recovery from current TBIs. The large percentage of ADSMs who present with clinically-elevated mental health symptoms after treatment may suggest the need for additional resources to address mental health needs before, during, and after treatment in TBI programs.