BEIJING, Jan. 31 (Xinhuanet) -- A study on 2,525 U.S. soldiers from two Army infantry brigades back from Iraq showed that those suffered concussion were at higher risk for post-traumatic stress disorder, according to Wednesday's New England Journal of Medicine.

    The soldiers were back home for three to four months after serving a year-long period in Iraq.

    The investigators found that 384 of the soldiers, or 15 percent, reported at least one concussion, which means an injury from a blow or shock to the head that causes temporary confusion or loss of consciousness, without any visible brain damage.

    Nearly 44 percent of the soldiers who had the symptom were diagnosed as PTSD, about three times the rate found in soldiers with other injuries.

    The finding suggests that mild brain injuries have a significant psychological component, which can improve with treatment, said Richard A. Bryant, a psychologist at the University of New South Wales in Australia.

    It would help soldiers realize that they have a brain injury that would not cause permanent damage.

    "This study is a very good first step, and an important one, it should lead us to ask further questions about these injuries," said Brian Levine, a neuropsychologist at the Rotman Research Institute and the University of Toronto, who was not involved in the study.

    The next step should be to assess troops' cognitive functioning early on and track it over time, before and after combat, said Levine.     

    (Agencies)