The role of traumatic brain injury — blamed for symptoms plaguing thousands of soldiers returning from Iraq — might be overstated, contends a provocative military study that offers hope for successful treatment.

In many cases, post-traumatic stress and depression may be driving the symptoms, doctors reported yesterday. And that’s good news because those are treatable. Returning soldiers have struggled with memory loss, irritability, trouble sleeping, and other problems. Many have suffered mild blast-related concussions, but there is no easy way to separate which symptoms are due to physical damage and which are from mental problems caused by the traumatic stress of war. Imaging of the brain is being tested, but hasn’t yet proved to be helpful.

The new study, based on a survey of 2,525 soldiers, found that brain injury made traumatic stress more likely. The study tied only one symptom — headaches — specifically to brain injury.

“We found that the symptoms and health concerns that we expected to be due to the concussion actually proved to be more strongly related to PTSD,” or post-traumatic stress disorder, and depression, Dr. Charles Hoge, a colonel and psychiatry chief at Walter Reed Army Institute of Research who led the study, said.

[Meanwhile, the Los Angeles Times reported that an Iraqi television cameraman for a Shiite-backed satellite news station was killed when a roadside bomb detonated near a security checkpoint in Balad, about 50 miles north of the capital. The blast also killed a driver and seriously injured a female reporter, who remains hospitalized, station officials said yesterday.

Iraq has become the world’s deadliest place to cover a story, according to the Committee to Protect Journalists.]