Variable, not always persistent, postconcussion symptoms after mild TBI in U.S. military service members: a five-year cross-sectional outcome study.

This study examined postconcussion symptom reporting within the first 5 years after mild traumatic brain injury (mTBI). Participants were 167 U.S. military service members (mean age, 27.6 years; 74.3% blast; 96.4% male) who were evaluated subsequent to injuries sustained in theater during Operations Iraqi and Enduring Freedom (92.8%) or from other combat-related operations. Participants completed the Neurobehavioral Symptom Inventory and Post-Traumatic Stress Disorder Checklist within 3 months of injury and at least one follow-up telephone interview at 6 (n = 46), 12 (n = 89), 24 (n = 54), 36 (n = 42), 48 (n = 30), and/or 60 months (n = 25) postinjury. Approximately half of the sample (49.7%) met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) symptom criteria for postconcussion disorder (PCD) at baseline. At all six follow-ups, 46.1-72.0% met DSM-IV criteria for PCD. However, only 20.4-48.0% reported persistent PCD from baseline to follow-up. A substantial minority had also improved (4.0-24.1%) or "developed" new symptoms (16.9-27.8%). Using regression analyses, baseline symptoms were somewhat predictive of PCD symptom reporting at follow-up, though this was not always reliable. Follow-up for all service members who sustain a combat-related mTBI in the context of polytrauma, regardless of the presence or absence of symptom reporting in the acute recovery stage, should be considered the rule, not the exception.