Amid growing alarm at the rate of suicide among members of the military and confusion about possible causes, researchers reported Monday that most of the Army's enlisted men and women with suicidal tendencies had them before they enlisted and that those at highest risk of making an attempt often had a long history of impulsive anger.

The new research — contained in three papers posted online Monday by the journal JAMA Psychiatry — found that about one in 10 soldiers qualified for a diagnosis of "intermittent explosive disorder," as it is known to psychiatrists, more than five times the rate found in the general population. This impulsive pattern, in combination with mood disorders and the stresses of deployment, increased the likelihood of acting on suicidal urges.

The new papers bring together five years of work by a coalition of academic, government and military researchers, investigating hundreds of suicides and surveying thousands of active soldiers in anonymous questionnaires.

The effort began in 2008, after the suicide rate among active soldiers rose above the civilian rate among young healthy adults for the first time.