MONDAY, Feb. 23 (HealthDay News) -- Headaches have become a common complaint among soldiers who suffered mild head trauma while serving in Iraq or Afghanistan.

These headaches tend to be debilitating, mirroring migraines in intensity, according to research released Monday that is to be presented next month at the American Academy of Neurology's annual meeting in Seattle.

About 15 percent of soldiers deployed to Iraq experience mild traumatic brain injury (TBI), according to background information from the researchers, who are based at Madigan Army Medical Center in Tacoma, Wash.

But not much has been known about the headaches that can occur as a result.

Research presented at the AAN meeting last year determined that almost 20 percent of U.S. soldiers returning from Iraq are being diagnosed with migraines. This group also has nearly double the risk for depression, post-traumatic stress disorder and other psychiatric troubles.

For this new study, 978 soldiers returning from Iraq and Afghanistan filled out 13-item questionnaires. Almost all of the participants were male, average age 27, and all had been stateside less than three months at the time of the interview.

All had suffered a concussion or head injury or experienced a blast exposure while overseas, and 97.8 percent reported having headaches.

On average, men (and some women) experienced headaches 8.4 days per month; average duration was 4.4 hours. Thirty percent of these soldiers had headaches 15 or more days each month.

In slightly more than two-thirds of respondents, the headaches started within one week of the injury or blast. Headaches started within one to four weeks in 20 percent of these soldiers.