Feature

As suicide rates rise, researchers separate thoughts from actions

Better understanding of risk factors could help those contemplating taking their own lives

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3:54pm, December 29, 2015
depressed soldier

OVER THE EDGE  There’s a wide chasm between contemplating suicide and taking action to end one’s life. Researchers are getting a clearer sense of the factors involved and are helping military personnel at greatest risk. 

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Craig Bryan treats military personnel who struggle with thoughts of ending their own lives, as well as those who’ve survived an actual suicide attempt. But these days he’s fighting an uphill battle.

Suicide rates in the United States have been rising, especially among veterans and members of the armed forces. Traditional assumptions about why people kill themselves have not led to effective strategies for suicide prevention, Bryan says. So in recent years psychologists and others have been reconsidering basic beliefs about why people carry out the ultimate act of self-destruction.

“There has been an explosion of new thinking about suicide in the past decade,” says Bryan, a clinical psychologist at the University of Utah in Salt Lake City.

This shift in focus was inspired by psychologist Thomas Joiner’s introduction in 2005 of the interpersonal theory of suicide. Unlike previous theorists, Joiner, of Florida State University in Tallahassee, treated thinking about suicide and attempting suicide as separate experiences, each with its own explanations and risk factors.

Joiner’s approach has inspired much new suicide research by Bryan and others. One line of work suggests that three factors render individuals especially prone to moving from suicidal thoughts to actions: a partly inborn ability to withstand pain, self-hate triggered by extremely distressing experiences and, finally, access to guns or other lethal means.

The same factors appear to hold true among military personnel. Combat soldiers are fearless and relatively impervious to pain, even before enlisting, according to recent studies. Personal traits that may predispose people to volunteer for combat may also up their chances of attempting suicide if war experiences trigger intense guilt and shame.

A new view

Between 1986 and 2000, U.S. suicide rates dropped from 12.5 to 10.4 deaths for every 100,000 people. But since then, the suicide rate has climbed steadily, reaching 12.6 deaths per 100,000 people, or more than 41,000 deaths, in 2013. That continuous rise — and the lack of effective counter-measures — has prompted researchers to revisit the suicide theories found in textbooks.

More than a century ago, sociologist Emile Durkheim proposed that severed bonds between an individual and his or her community are crucial factors in suicide. Others have held that people kill themselves to escape intolerable pain, feelings of hopelessness or depression and other mental disorders.

But evidence suggests there’s more to it: Most people who contemplate suicide never actually try to kill themselves. A 2008 study estimated that for every person who attempts suicide, about three others have considered suicide but never acted on those thoughts.

In Joiner’s theory, being convinced that one is a burden to others and, at the same time, feeling isolated or unimportant bring on suicidal thoughts. But taking one’s own life is a scary prospect, even for those who regard themselves as disposable liabilities, Joiner reasoned. Overcoming an ingrained survival instinct to make a suicide bid requires a person to have a reduced fear of death and considerable tolerance for physical pain, probably acquired via harsh life experiences, he proposed.

Joiner’s ideas have caught on as the limits of depression and other mental ailments as predictors of suicide have become obvious.

As early as 1999, a national survey of psychiatric disorders led by psychiatric epidemiologist Ronald Kessler of Harvard Medical School found an excess of self-reported suicidal thoughts — but not of documented suicide attempts — among people with depression or several other mental conditions.

Studies since then have found that psychiatric disorders as well as two other characteristics traditionally viewed as suicide risk factors — feelings of hopelessness and a tendency to act impulsively — only weakly predict whether individuals have attempted suicide or will try to end their own lives in the coming weeks or months, says psychologist E. David Klonsky of the University of British Columbia in Vancouver. Klonsky directed several of those investigations.

Inspired by Joiner’s approach, Klonsky and British Columbia colleague Alexis May proposed what they call the three-step theory of suicide in the June International Journal of Cognitive Therapy.

In step one, a combination of physical or emotional pain and hopelessness spurs thoughts of killing oneself. “Depression and other traditional risk factors matter to the extent that they increase hopelessness and pain,” Klonsky says.

Second, he and May suggest that suicidal thoughts further intensify for people who lack connections to loved ones, to valued roles or to any sense of purpose in life.

Finally, echoing Joiner, the researchers hold that suicide attempts occur only among people with a low sensitivity to pain — a partly genetic trait, according to studies of animals, human genetic variants and human twins — and an ability to overcome fears of death.

Klonsky and May conducted an online survey of 910 U.S. adults, ages 18 to 70, that supports the three-step theory. Participants who reported having contemplated or planned a suicide — 27 percent of the sample — described especially high levels of preexisting pain or hopelessness, the researchers report in their June paper. Those who said they had never considered suicide, even if they had experienced pain and hopelessness, reported having close friends and relatives and usually were involved in activities they found meaningful. The 14 percent of participants who reported that they had tried to kill themselves — a higher figure than in the general population — cited relatively few fears of dangerous situations and physical pain. They were also more likely to know about and have access to guns or other lethal methods.

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Primed for danger

Joiner originally proposed that a buildup of painful and provocative experiences cultivates the fearlessness and pain tolerance needed to attempt suicide. Building on that theme, many researchers suspect that increasing numbers of soldiers have killed themselves because military training followed by combat desensitized them to death’s pain and finality.

But new findings from a team led by Bryan challenge that scenario. Many soldiers who encounter war violence grow up with an elevated “set point” of fearlessness and pain tolerance that prompts them to seek out harsh and provocative experiences, such as combat, Bryan suggests. As a result, these soldiers run a heightened risk of encountering wartime horrors that spark suicide-promoting reactions such as guilt, shame and self-hate.  

This is an urgent issue. In 2009, the military suicide rate surpassed that of the general population for the first time since at least 1977. From 2009 to 2012, suicides increased from 18.5 to 22.7 out of 100,000 active-duty service members. Those numbers declined in 2013, the latest year in which data are available, although it’s too early to say whether that’s the beginning of a downward trend.

Determining how soldiers move from suicidal thoughts to actions is essential for developing better therapies, Bryan says.

To check the popular assumption that combat experiences groom soldiers for suicide, Bryan and his colleagues studied 168 U.S. Air Force members, mostly men, working as ground convoy operators. At the beginning and end of three months of training before deployment overseas, the soldiers completed a questionnaire on suicide capability, a measure of the likelihood of turning one’s suicidal thoughts into actions developed by Joiner’s team. Once they returned from a nine-month mission to Iraq in 2009, participants completed the same questionnaire at four points during the next year.

Participants rated their fearlessness in general, their fear of death, their ability to withstand pain and their preference for contact sports and other aggressive pastimes.

Combat didn’t change their self-reported fearlessness, pain tolerance and susceptibility to attempting suicide. Suicide capability scores were just as high before deployment as afterward, even among convoy operators whose overseas stints exposed them to plenty of disturbing, combat-related events, Bryan’s group reported August 11 in Clinical Psychological Science. Those incidents included being attacked or ambushed, being shot at and seeing dead bodies or severed body parts.

Comparably elevated suicide capability scores have been reported in combat veterans as well as in new military personnel, Bryan says.

Having a preexisting capacity for suicide is not enough, however, to push someone over the edge. Evidence increasingly suggests that the way current and former soldiers judge themselves and their wartime actions helps to explain why some burdened by symptoms of depression and post-traumatic stress try to kill themselves and others don’t. In the last several years, Bryan’s team has found particularly intense thoughts of suicide among soldiers with depression and PTSD who also report guilt, shame and self-hatred stemming from having committed or witnessed wartime acts that violated their moral beliefs. Those soldiers are perilously close to attempting suicide, the researchers suspect. Some clinicians are working to tamp down the self-hatred with specific forms of therapy.

A 12-session course of cognitive-behavioral therapy aimed at altering guilt- and shame-related beliefs showed promise with Army personnel who were briefly hospitalized following suicide attempts or who reported having serious suicidal thoughts, say University of Memphis psychologist M. David Rudd and colleagues, including Bryan. Most of the soldiers had been deployed one or more times.

In the two years after they had received the cognitive-behavioral therapy treatment, eight of 76 soldiers made at least one suicide attempt, the researchers reported last May in the American Journal of Psychiatry. During the same period, 18 of 76 soldiers who received traditional forms of talk therapy and medication tried to kill themselves at least once. One soldier in each group died by suicide.

Combat protection

Rudd and Bryan see a future for treatments that target emotions such as guilt in soldiers who are apt to act on their suicidal thoughts. Those suicide-prevention efforts will probably need to be tailored to different branches of the military, says Robert Ursano of the Uniformed Services University of the Health Sciences in Bethesda, Md. Ursano is the coleader of Army STARRS, the largest study of military mental health ever conducted. Army STARRS investigators have access to medical and hospital records of more than 1.6 million active-duty Army soldiers from 2004 through 2009.

Ursano sees this massive investigation as an opportunity to explore why some soldiers ponder but reject suicide, others plan ways to kill themselves but stop short of doing so and a third group follows through on suicidal plans.

Bryan’s finding that an elevated tendency to attempt suicide stems from preexisting traits, rather than from combat experiences, among Air Force convoy operators may not apply to other military branches, Ursano holds. Army soldiers and Marines, for instance, may get deployed to more intense war zones than Air Force personnel do, Ursano says. In those cases, brutal combat incidents may represent larger contributors to soldiers’ risk of suicide, he suspects.

But Bryan has a point, Ursano concedes. There are suggestions that Army personnel who choose combat duty — in the U.S. military, such duty isn’t mandatory —  display elevated suicide rates before deployment, in line with Bryan’s findings for Air Force convoy operators. Army STARRS data published in the November Psychological Medicine show that, between 2004 and 2009, Army infantrymen and combat engineers killed themselves at substantially higher rates before and after deployment than while stationed overseas. A sensation-seeking personality or other background characteristics may serve these soldiers well in war zones, but boost the odds that they’ll become suicidal before and after their tours of duty, suggests Harvard psychologist and study coauthor Matthew Nock.

Intense camaraderie during deployment may also discourage suicides while soldiers are actively in combat, Nock adds.  

Enlisted soldiers in noncombat jobs and those who performed construction and demolition tasks under combat conditions killed themselves more often during and after deployment, not before. That’s consistent with the possibility that soldiers in those jobs were already fearful and pain-sensitive enough to have a relatively low suicide risk. However, the stress, loneliness and uncertainty of spending months on the front lines may nudge them into self-harm’s way.

These findings come from an Army STARRS team led by Harvard’s Kessler that analyzed suicide patterns among combat and noncombat personnel. The researchers examined administrative data on the 729,337 men enlisted in the Army from 2004 to 2009, including 496 who took their own lives.

Other suicide trends are emerging from Army STARRS. One investigation found elevated suicide rates among personnel during their first four years after enlisting, whether deployed in combat or noncombat positions. Army women also kill themselves considerably more often while deployed.

Traditional notions of combat as the primary culprit in prompting military suicides appear destined for extinction. “The association between deployment and suicide is not as simple as we expected,” Nock says.

Fluctuating risks

In the general population as well as in the military, it’s hard to know when someone who is unafraid of death, wracked by self-hatred and plagued by other suicide risks will tumble over the edge. For insight into precisely when suicidal thoughts turn into actions, some scientists are tracking risk factors that come and go, some from one moment to the next.

Memphis’ Rudd theorizes that certain personal characteristics linked to a heightened risk of suicide are stable, such as being a man or having survived personal traumas early in life. Other risks fluctuate, such as bouts of depression, arguments with friends and money troubles. As stable risk factors add up, Rudd predicts, fluctuating risk factors become increasingly able to instigate suicide attempts.

The pull of accumulating risks can be offset by protective factors, such as a supportive family or landing a new job. Rudd calls his approach fluid vulnerability theory.  

Psychologist Courtney Bagge of the University of Mississippi Medical Center in Jackson recently led a rare effort to identify behaviors and events that intensified suicidal thinking among people shortly before they tried to kill themselves.

Bagge and her colleagues recruited 166 men and women who received hospital care within a day after making a suicide bid. In interviews, participants carefully rehashed what had happened in the 24 hours leading up to those attempts.

Alcohol drinking and upsetting personal experiences typically triggered spikes in thinking about suicide shortly before patients tried to end their lives, the researchers reported in 2014 in the Journal of Affective Disorders. Distressing events reported by volunteers included fights with a loved one and receiving bad health or financial news.

If these findings hold up, suicide-prevention treatment will need to help clients develop strategies to squelch booze-drinking urges and to cope with sudden setbacks, the researchers say. Fast responses are crucial. In other studies, Bagge has found that the majority of suicide attempters report devising or recalling a plan to kill themselves and deciding to act on that plan within three hours of actually attempting suicide.

People in distress may also hurt themselves without suicidal intent. Examples include cutting, burning or hitting oneself. But such behavior may serve as an early warning. Nock and other researchers have found a strong risk for suicide attempts among people who harm themselves in these ways.

A team led by psychologist Teena Willoughby of Brock University in St. Catharines, Canada, measured college students’ suicide capabilities in their freshman year and again one year later. Those who reported frequently cutting or otherwise injuring themselves during that year cited substantial drops in pain sensitivity and death fears — Joiner’s cardinal signs of suicide capability — from their freshman to sophomore years.

Joiner has also argued that, based on his interpersonal theory, nonsuicidal forms of hurting oneself — say, repeatedly slicing one’s skin with a razor blade or hitting oneself to the point of bruising — are painful and provocative enough to promote suicide attempts. The new findings lend support to that idea, Willoughby’s team concludes in the November Journal of Abnormal Psychology.

Still, most college students don’t try to end their own lives, whether or not they intentionally harm themselves. Neither do most combat veterans. Neither do people in any other segment of society. So why does a growing minority of the population view self-destruction as an option?

The way forward in suicide prevention lies in determining how stable and fluctuating risks for suicide interact to push people over the edge, Bryan says. The trick will be to equip individuals with the equivalent of an emotional GPS system that steers clear of the abyss, a place where dire thoughts can lead to death at one’s own hand.


This article appears in the January 9, 2016, issue of Science News under the headline, "Over the Edge: What leads a person to move from thinking about suicide to taking action?"

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