RENEE MONTAGNE, host:
This is MORNING EDITION from NPR News. I'm Renee Montagne. Good morning.
Traumatic brain injury has been labeled the signature injury of the Iraq war. Now a study published in The New England Journal of Medicine finds that even minor brain injuries - concussions - are associated with long-term health problems, specifically post-traumatic stress disorder.
NPR's Alix Spiegel has this story.
ALIX SPIEGEL: Army medic Tim Bredberg's first concussion happened during a routine patrol of the Iraq desert. It was late afternoon when the road he was on narrowed abruptly, creating a bottleneck more or less in the middle of nowhere.
Mr. TIM BREDBERG (Army Medic): We were going through this and two other vehicles went before us, and we're thinking, okay, we're safe. And we drove by and then the next thing I know, I wake up in the middle of a firefight.
SPIEGEL: Besides a concussion, Bredberg was unhurt. For two days he says his ears rang and his eyes were sensitive to light, but there were no other symptoms. And Bredberg says he didn't really feel rattled by the experience in any real way.
Mr. BREDBERG: Not that I noticed. If anything, I was more pissed off and wanted to get out there even faster.
SPIEGEL: Over the course of his time in Iraq, Bredberg was hit by IEDs three other times and suffered another concussion. But again, he didn't notice any lasting effects. But then Bredberg returned to the U.S. and he began having nightmares, dreams of violence so intense he didn't want to sleep. Bredberg says he would startle at the slightest noise. There are flashbacks and wild mood swings. His relationships began to deteriorate. He found it difficult even to be near his infant son.
Mr. BREDBERG: I couldn't be around my son because of flashbacks when he cried.
SPIEGEL: But perhaps the scariest moment came one weekend when Bredberg was out at a store. A man passed him and Bredberg remembers him saying something vaguely rude.
Mr. BREDBERG: The next thing I know I have people from this grocery store yelling at me and grabbing at me because I'm beating the hell out of this guy in the parking lot. And I didn't realize it. I didn't know I was doing it.
SPIEGEL: Bredberg finally went to mental health on his base at Fort Drum. He says he was told by the doctors there that he had PTSD. Now a study published in The New England Journal of Medicine suggests there may be a relationship between concussions and the development of post-traumatic stress disorder.
Army medical researcher Charles Hoge surveyed over 2,000 Army infantry soldiers who had returned from Iraq and found that three to four months after their return a high percentage of those who had experienced a concussion met the criteria for post-traumatic stress disorder.
Dr. CHARLES HOGE (Walter Reed Army Institute of Research): Nearly half of soldiers who had a concussion with loss of consciousness met the criteria for PTSD, and that's a very high rate.
SPIEGEL: Hoge says he was a little surprised by these results because in the civilian world concussions aren't generally associated with PTSD.
Dr. HOGE: For instance, on a football field, football players certainly don't develop post-traumatic stress disorder in the context of football injuries and concussions on the football field.
SPIEGEL: Hoge says one possible explanation is that traumatic battles produce both concussions and PTSD. But another researcher, David Hovda, a professor of neurosurgery at UCLA, suggests another possibility. He points out that there are real chemical changes in the brain in the wake of a concussion.
Professor DAVID HOVDA (UCLA): And this change in chemistry causes other things to change, which have long-term consequences with regards to how the brain response to emotions.
SPIEGEL: So, says Hovda, though concussions don't cause post-traumatic stress disorder, the chemical changes that are the product of concussion and the lethargy, anxiety and depression that often follow, may inhibit a person's ability to recover from a traumatic experience.
Three and a half years after his return from Iraq, Tim Bredberg continues his fight with the disease, but says he is somewhat better able to cope with his child's cry.
Mr. BREDBERG: It is getting a little bit better. I mean, I can be around him for a certain amount of time if he cries. Like if I feel myself hitting a flashback when I'm around him, I can control it to a point. Just repeat to myself that, you know, everything is okay. My wife is in the other room. I'm sitting in the bathroom. You know, just keep going through things like that.
SPIEGEL: Alix Spiegel, NPR News, Washington.