Staff Perspective: A Brief Update on Post-Concussion Syndrome in Deployed Service Members

Staff Perspective: A Brief Update on Post-Concussion Syndrome in Deployed Service Members

Since 2001, more than 2.6 million U.S. military personnel have been deployed in support of Operations Enduring Freedom, Iraqi Freedom, and New Dawn1. Between 2001 and 2016, more than 350,000 cases of traumatic brain injury (TBI) have been diagnosed in active duty Service members, most of which are concussive TBI (cTBI), also known as mild TBI2. While most Service members with cTBI achieve a full recovery in three months or less, a substantive proportion exhibit post-concussion syndrome (PCS), or post cTBI symptoms occurring beyond three months. The most commonly reported symptoms are difficulty sleeping, forgetfulness, irritability, headaches, and fatigue3.

There is undoubtedly a role of comorbid mental health concerns in PCS and clearly the symptoms of mental illness and PCS overlap (e.g., difficulty sleeping, irritability, etc.). However, PCS symptom severity has been consistently linked to white matter abnormalities4 and recent longitudinal studies found that cTBI is associated with PCS even when accounting for posttraumatic stress (PTS)3,5. For example, a recent cohort study of Service members returning from Afghanistan or Iraq determined that rates of PCS were 71% in soldiers who sustained a cTBI and exhibited PTS, 41% in soldiers who sustained a cTBI but no PTS, and 25% in controls (no cTBI and 5% had PTS)3. Furthermore, research has identified prognostic factors for PCS including history of TBIs, pre-deployment distress, deployment distress, and loss of consciousness from cTBI(s)5. This research suggests the following:

  1. Most Service members with cTBI recover within three months, and many recover much sooner than that.
  2. However, a substantive number of Service members do experience PCS.
  3. In many Service members with PCS, their symptoms are explained by co-occurring mental illness. However, studies indicate a minority of Service members have PCS that is partially or entirely independent of co-occurring mental illness.
  4. Research has found an association of PCS severity with non-psychological factors such as pre-deployment TBI, loss of consciousness, and white matter abnormalities.

These recent research findings indicate the utility of working with an integrated care team. It is difficult to disassociate mental illness from true PCS because often both psychological and medical factors are implicated. It is therefore important to balance the likelihood of a positive prognosis for cTBI and PCS, with the knowledge that for some Service members, there may be persisting PCS that are largely distinct from psychological factors.

The opinions in CDP Staff Perspective blogs are solely those of the author and do not necessarily reflect the opinion of the Uniformed Services University of the Health Science or the Department of Defense.


1. Medicine I of. Treatment for Posttraumatic Stress Disorder in Military and Veteran Populations: Final Assessment. Washington, DC: National Academies Press, 2014.
2. DoD Worldwide Numbers for TBI.
3. Schwab K, Terrio HP, Brenner LA, et al. Epidemiology and prognosis of mild traumatic brain injury in returning soldiers: A cohort study. Neurology. 2017;88:1571–9.
4. Khong E, Odenwald N, Hashim E, et al. Diffusion Tensor Imaging Findings in Post-Concussion Syndrome Patients after Mild Traumatic Brain Injury: A Systematic Review. Front Neurol. 2016;7:156.
5. Stein MB, Ursano RJ, Campbell-Sills L, et al. Prognostic Indicators of Persistent Post-Concussive Symptoms after Deployment-Related Mild Traumatic Brain Injury: A Prospective Longitudinal Study in U.S. Army Soldiers. J Neurotrauma. 2016;33:2125–32.
6. Adams RS, Corrigan JD, Mohr BA, et al. Traumatic Brain Injury and Post-Deployment Binge Drinking among Male and Female Army Active Duty Service Members Returning from Operation Enduring Freedom/Operation Iraqi Freedom. J Neurotrauma. 2017;34:1457–65.