War is the intentional infliction of harm on the enemy, on the battlefield. It is not supposed to provide an opportunity for soldiers to end their own lives.

Yet the suicide rate among American troops who served during the Iraq and Afghanistan wars, including those who never deployed overseas, rose sharply. That development is the focus of a $65 million research study and survey.

Initial findings, published in the journal JAMA Psychiatry, are unsettling. Suicide rates among soldiers doubled from 2004 to 2009, during the height of the U.S. presence in Afghanistan and Iraq, to as many as 30 per 100,000 troops.

In that period, 569 soldier deaths were determined to be suicides. More recently, the soldier suicide rate has dropped back toward 20 per 100,000 — close to the U.S. civilian rate.

The Defense Department is studying several factors in an attempt to explain the increase in suicides. One is the multiple deployments that many members of the all-volunteer force endured.

Another is the fact that most enlisted men and women with suicidal tendencies exhibited them before joining the military. The new research shows that an estimated one in 10 soldiers qualified for a diagnosis of “intermittent explosive disorder” before he or she puts on a uniform.

Today, about a quarter of the soldiers surveyed — twice the rate of the general population — are believed to have at least one psychiatric disorder on a list that includes depression, substance abuse, and anxiety. A more-troubling statistic may be the rate of explosive rage and impulsiveness — 11 percent among soldiers versus 2 percent among civilians.

More research on the causes of anger, despair, and suicide in the Armed Forces is a start. More important will be the willingness of Pentagon leaders to respond to these tendencies, and the factors that cause them.

War is hell enough already. It shouldn’t be self-inflicted too.

First Published March 7, 2014, 5:00 a.m.