More than 40% of US soldiers deployed in Iraq who had injuries associated with a loss of consciousness met criteria for PTSD, reported researchers in the January 31 New England Journal of Medicine. In turn, PTSD, as well as depression, was associated with poor general health, missed workdays, medical visits, and a high number of somatic and postconcussive symptoms.

Charles W. Hoge, MD, Director of the Division of Psychiatry and Neuroscience at Walter Reed Army Institute of Research in Silver Spring, Maryland, and colleagues surveyed 2,525 US Army infantry soldiers (95.5% men) three to four months after their return from a yearlong deployment to Iraq. About 5% of soldiers reported injuries with a loss of consciousness that lasted between a few seconds and two or three minutes; of them, 43.9% met criteria for PTSD, a rate significantly higher than that among soldiers who reported injuries with altered mental status (27.3%), other injuries (16.2%), or no injuries (9.1%) during deployment.

After the researchers controlled for other factors, they found that soldiers who lost consciousness were nearly three times more likely to meet criteria for PTSD. “Injury with loss of consciousness was also independently associated with major depression (odds ratio [OR], 3.67),” noted the authors. Injury with altered mental status and combat intensity were also significantly and independently associated with PTSD (ORs, 1.78 and 6.63, respectively), but not with depression.

Soldiers who lost consciousness were also significantly more likely to report poor general health, more missed workdays, and a higher number of medical visits in the past month than were soldiers with other injuries, reported Dr. Hoge and colleagues. Total scores on the Patient Health Questionnaire 15-item somatic symptom severity scale (PHQ-15) were also significantly higher among that group, as were rates of nine physical symptoms and all five postconcussive symptoms. However, these physical health problems occurred predominantly in the soldiers with PTSD.

Once PTSD and depression were included in the analysis of the relationship between loss of consciousness and multiple physical health outcomes, however, only the association with headache remained significant. “In contrast, PTSD, depression, or both were strongly associated with all the physical health outcomes in these adjusted models,” said the investigators. They hypothesized that loss of consciousness in combat represents a highly traumatic event (ie, a close call on one’s life) that can lead to PTSD and depression. These mental disorders can then lead to increased prevalence rates of physical health problems due to their association with neuroendocrine dysregulation and autonomic nervous system reactivity.

“The only intervention that has been proven to be effective in reducing symptoms following concussion is cognitive education to normalize symptoms and to provide the expectation for rapid recovery,” Dr. Hoge told NeuroPsychiatry Reviews. He and his coauthors suggested that physicians can improve risk communication by using the term “concussion” instead of “mild traumatic brain injury.” They also recommended a multidisciplinary approach centered in primary care to evaluate and treat the symptoms and coexisting mental disorders experienced by these patients.

—Jessica Dziedzic

Suggested Reading
Hoge CW, McGurk D, Thomas JL, et al. Mild traumatic brain injury in U.S. soldiers returning from Iraq. N Engl J Med. 2008;358(5):453-463.

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