Postconcussive Symptoms (PCS) Following Combat-related Traumatic Brain Injury (TBI) in Veterans with Posttraumatic Stress Disorder (PTSD): Influence of TBI, PTSD, and Depression on Symptoms Measured by the Neurobehavioral Symptom Inventory (NSI)

Mild traumatic brain injury (mTBI) is commonly reported in recent combat Veterans. While the majority resolve, some Veterans develop postconcussive symptoms (PCS). Previous research suggests these symptoms are not specific to head injury and are often associated with psychiatric symptoms. The current study examines the relative contributions of posttraumatic stress, depressive symptoms, and TBI on postconcussive symptoms, and explores whether the relationship remains after controlling for symptom overlap. Two hundred eighteen combat Veterans from Operation Iraqi Freedom (OIF), Operation Enduring Freedom (OEF), and Operation New Dawn (OND) provided the data for this study as part of a baseline evaluation for inclusion into larger treatment study for posttraumatic stress disorder (PTSD). Participants completed the Brief Traumatic Brain Injury Screen (BTBIS), Neurobehavioral Symptom Inventory (NSI), PTSD Checklist-Stressor Version (PCL-S), Beck Depression Inventory-II (BDI-II). Significant differences in NSI total score between individuals with and without history of TBI were not found. A series of regression analyses demonstrated that Depression and PTSD were significant predictors of NSI score even after removal of NSI symptoms that overlap with PTSD or depression. TBI status was also a significant predictor of PCS in most models, but its relative contribution was much smaller than that of depression and PTSD. Within PTSD symptoms, hyperarousal cluster was a significant predictor of NSI scores. Findings demonstrate that depression and PTSD are related to PCS beyond similarities in construct. Further, within a primarily PTSD treatment-seeking population, these psychiatric symptoms appear to be a stronger contributor than TBI.