NEW YORK — 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 findings were contained in three papers posted online Monday by the journal JAMA Psychiatry, including research done at Harvard University.
The studies 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. The wars in Iraq and Afghanistan have relied on an all-volunteer Army, not a draft as in previous wars. And many of today’s enlisted men and women have deployed two, three, sometimes four times.
The new reports provide the first glimpse at how changes in the makeup of the fighting force and the increased demands of service have affected the suicide rate. The annual soldier suicide rate more than doubled between 2004 and 2009, to over 23 per 100,000. In that period, 569 soldier deaths were ruled suicides. Since then, the rate has begun to fall back toward 20 per 100,000, the civilian rate in the same age group.
“This effort will do for suicide what the Framingham Heart Study did for cardiology, provide for the first time a way to look at multiple factors over a huge number of people,” said Dr. David Brent, a psychiatrist at the University of Pittsburgh who was not involved in the research.
The results, he added, strongly suggest that “the baggage people bring with them and often don’t disclose in order to get into armed services presumably interacts with the stresses of deployment” to increase vulnerability to suicide.
The three reports do not settle whether accession waivers, which relax standards for new soldiers and which the Army has used to shore up its ranks, increased the force’s vulnerability to suicide.
One study, an investigation of suicides and accidental deaths led by Michael Schoenbaum of the National Institute of Mental Health, found a host of risk factors many have suspected: demotions, a lower rank, and previous deployment among them. But looser standards for enlistment were not correlated with increased suicides.
Overall, the three reports sketch a portrait of suicide risk that in many respects is like the civilian one. About 14 percent of the surveyed soldiers said they’d had suicidal thoughts, and 5 percent had made plans to take their lives at least once — mirroring the rates among civilian peers. About 2 percent had actually made an attempt. (The attempt rate for civilians is actually twice as high, but soldiers’ attempts are more lethal.)
About a quarter of soldiers surveyed qualified for at least one current psychiatric disorder, such as depression, anxiety, or substance abuse. That is roughly twice the rate among peers in the general population, but only about half of those disorders developed after enlistment.
The biggest difference between soldiers and young adults in the civilian population was in impulsive anger. The rate was more than 11 percent among surveyed soldiers and less than 2 percent among young civilians. The anger issues predated enlistment about three-quarters of the time, said Matthew Nock, a lead author on one of the papers and a psychologist at Harvard University.
“The people at highest risk of making an attempt struggled with depression and anxiety, or post-traumatic stress, in combination with impulsiveness and aggression,” Nock said. “The former gets people thinking about suicide, and the latter gets them to act on those thoughts.”
Some experts suggested that the services could screen people after enlistment, to identify those who might be offered additional support.
“A small minority of soldiers are responsible for a disproportionate amount of suicidal behavior,” wrote Dr. Matthew J. Friedman, of the National Center for PTSD, in an editorial accompanying the reports. “Better identification of and intervention with the cohort are likely to have the best payoff.”
These experts also said that the military could invest in courses that shore up mental toughness servicewide as a preventive measure.