A study of active duty U.S. Marines who suffered a recent or previous concussion(s) examined whether persistent post-concussive symptoms (PPCS) and lingering effects on cognitive function are due to concussion-related brain trauma or emotional distress. The results are different for a recent concussion compared to a history of multiple concussions, according to the study published in Journal of Neurotrauma, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available Open Access on the Journal of Neurotrauma.

James Spira, U.S. Department of Veterans Affairs and University of Hawaii (Honolulu, HI), Corinna Lathan, AnthroTronix, Inc. (Silver Spring, MD), Joseph Bleiberg, Walter Reed National Military Medical Center (Bethesda, MD), and Jack Tsao, U.S. Navy Bureau of Medicine and Surgery (Falls Church, VA), assessed the effects of concussion on persistent symptoms, independent of deployment history, combat exposure, and symptoms of post-traumatic stress disorder and depression. They describe the results for persons with a recent concussion or who had ever had a concussion to those who had more than one lifetime concussion in the article "The Impact of Multiple Concussions on Emotional Distress, Post-Concussive Symptoms, and Neurocognitive Functioning in Active Duty United States Marines Independent of Combat Exposure or Emotional Distress".

John T. Povlishock, PhD, Editor-in-Chief of Journal of Neurotrauma and Professor, Medical College of Virginia Campus of Virginia Commonwealth University, Richmond, notes that "This study by Spira and colleagues represents an important contribution to our understanding of the negative impact of multiple concussions in a relatively large military population sustaining both deployment and non-deployment related trauma. The consistent observation that multiple concussive injuries are associated with worse emotional and post-concussive symptoms is an extremely important finding that must guide our evaluation of individuals, in both the military and civilian settings, who have sustained multiple concussive injuries. While the authors acknowledge some limitations of the current work and the need for future research to follow a similar cohort in terms of the time course and causality of the symptoms associated with concussion, overall this well done study adds significantly to our increased understanding of the adverse consequences of repetitive concussive/mild traumatic brain injury."