Influence of bodily injuries on symptom reporting following uncomplicated mild traumatic brain injury in US military service members

Objective: To examine the relations among bodily injuries, traumatic stress, and postconcussion symptoms in a sample of combat-injured US service members who sustained a mild traumatic brain injury. Participants: One hundred and thirty-seven service members evaluated and treated at Walter Reed Army Medical Center following medical evacuation from the combat theater of Operation Enduring Freedom and Operation Iraqi Freedom. All had sustained an uncomplicated mild traumatic brain injury and concurrent bodily injuries. Procedure: Participants completed 2 symptom checklists within 3 months of injury. Severity of bodily injuries was quantified with a modified version of the Injury Severity Score that excluded intracranial injuries (ISS _mod). Participants were classified into 4 ISS _mod groups: minor (n = 17), moderate (n = 48), serious (n = 40), severe/critical (n = 32). Main Outcome Measures: Neurobehavioral Symptom Inventory (NBSI) and the Posttraumatic Stress Disorder Checklist-Civilian version (PCLC). Results: There was a significant negative association between ISSmod scores and the NBSI and PCLC total scores. There were significant main effects across the 4 groups for the NBSI and PCLC total scores. The highest NBSI and PCLC scores were consistently found in the ISSmod minor group, followed by the moderate, serious, and severe/critical groups. Conclusions: While it might be expected that greater comorbid physical injuries would be associated with greater symptom burden, in this study as the severity of bodily injuries increased, symptom burden decreased. Hypothesized explanations include: underreporting of symptoms; increased peer support; disruption of fear conditioning due to acute morphine use; or delayed expression of symptoms.