Mild traumatic brain injury occurring among soldiers deployed in Iraq is strongly associated with posttraumatic stress disorder and physical health problems 3-4 months after the soldiers return home, according to survey findings.
Results from a survey of more than 2,000 soldiers who had served in Iraq suggest that the relationship between mild traumatic brain injury and physical health problems is largely mediated by the presence of posttraumatic stress disorder (PTSD) and depression.
"The strong associations between mild traumatic brain injury, PTSD, depression, and physical health symptoms in combat veterans reinforce the need for a multidisciplinary approach centered in primary care," said Dr. Charles W. Hoge of the division of psychiatry and neuroscience at Walter Reed Army Institute of Research in Silver Spring, Md., and his associates.
A total of 2,714 soldiers completed the questionnaire, mailed in 2006 to soldiers from two U.S. Army combat infantry brigades--one active and one reserve--3-4 months after their return from a yearlong deployment in Iraq. The survey elicited information about whether soldiers had been injured, the nature of the injuries, and about the soldiers' physical and mental health (N. Engl. J. Med. 2008;358:453-63).
After exclusion of 149 for missing data and 40 with head injuries that did not involve loss of consciousness or altered mental status, the study group comprised 2,525 soldiers.
Of those, 5% (124) reported an injury with loss of consciousness. The majority of these episodes lasted between a few seconds to 2-3 minutes, but four soldiers reported having been unconscious for more than 30 minutes. Another 10% (260) reported an injury with altered mental status in which they did not lose consciousness. This 15% was defined as having mild traumatic brain injury.
Another 17% (435) reported some other injury during deployment with no loss of consciousness or altered mental status, most commonly resulting from a fall or injury during training. This spectrum of injury is likely to be representative of all soldiers serving in ground-combat units in Iraq, the investigators said.
Compared with the soldiers who had other injuries, those with mild traumatic brain injury were significantly more likely to report high combat intensity, a blast mechanism of injury, more than one blast exposure, and hospitalization while deployed. They were also significantly younger, more junior in rank, and more often male.
Overall, 44% of the soldiers who reported loss of consciousness met the criteria for PTSD, compared with 28% of those with altered mental status, 16% of those with other injuries, and 9% of those with no injuries. Loss of consciousness and combat intensity were the only two factors that remained significantly associated with PTSD after an analysis that took into account age, military rank, sex, hospitalization status, mechanism of injury, level of combat intensity, single vs. multiple blast exposure, and type of injury (loss of consciousness vs. other injuries).
Those with loss of consciousness were nearly three times as likely to have PTSD (odds ratio 2. …