At age 18, Erica Hernandez tried to kill herself—twice. Depressed and plagued by family problems, she first took “every pill in the house,” she says. Then she attempted to drink herself to death. But whether through luck or indecision, her attempts were not drastic enough to end her life before help arrived. Now age 31, Hernandez has found “peace” through her church and a parent-child psychotherapy group she has joined.

Every year millions of people around the world try to kill themselves—and nearly one million of them succeed. Suicide is the 11th biggest killer of Americans and the third-leading killer of 15- to 24-year-olds. The U.S. suicide rate is increasing for the first time in a decade, primarily as a result of the rise in the practice among whites aged 40 to 64, according to a new report covering the years 1999 to 2005 from the Center for Injury Research and Policy at the Johns Hopkins Bloomberg School of Public Health. The economy is now adding to the problem: the chief financial officer of Freddie Mac killed himself last April, and so have some Americans who have been evicted from their homes. The U.S. government’s National Suicide Prevention Lifeline, begun in 2005, is also getting record numbers of calls: 57,625 in August 2009, up from 47,191 the same month a year before.

Why? Researchers are refining the traditional ideas about who is at highest risk of following through on suicidal thoughts—and how to help prevent those individuals from doing so. In particular, they are finding that a motivation to die, whether a result of depression or another mental disorder perhaps accompanied by life circumstances, is only part of the story. “Virtually everyone who dies by suicide has a mental disorder at the time of death,” says psychologist Thomas E. Joiner of Florida State University and author of Why People Die by Suicide (Harvard University Press, 2005) and Myths about Suicide (Harvard University Press, in press for 2010). “But there are millions and millions of people with mental disorders who do not die by suicide.” What keeps them from carrying out this act?

It is not enough to want to die. To intentionally end their own life, people need the will to carry out their plans. This resolve depends on factors such as fearlessness and being able to tolerate pain and to act impulsively. The latest research shows that such fearlessness can be conditioned: those who gain experience with pain, whether from abuse by others or by their own hands, gradually improve their ability to tolerate discomfort; they also get used to the idea of harming themselves. Their risky forays can lead to suicide. Poor impulse control, sometimes fueled by alcohol or other substances, may spur suicidal acts.

“Death by suicide is never about one single thing,” says Richard McKeon, the lead public health adviser for the suicide prevention branch of the U.S. Substance Abuse and Mental Health Services Administration. “Most people who lose their jobs or lose their homes don’t kill themselves.” But they may find themselves in a perfect suicide storm if they feel sufficiently humiliated and hopeless and possess the will—the guts, some might say—to end their life.

Experts are using this new conception of suicide risk to identify those individuals most likely to try to end it all, to target them for preventive therapy. They are also focusing anew on deterrents that simply make the act of suicide more difficult to accomplish.

Signs of Sadness
Historically, suicide researchers tended to study sociological factors and mental illness, such as depression, that make people feel as though they want to die. But today they are also unearthing clues to help them identify individuals who have both lost the will to live and are most likely to carry out their plans to end it all. One risk factor for both elements is family history. In a 2002 study of 4,262 Danish suicide victims, Ping Qin and his colleagues at Aarhus University determined that having a family history of suicide raises your chances of the same fate by two and a half times. Indeed, last year Nicholas Hughes, the son of author Sylvia Plath (who stuck her own head in a gas oven), proved that he inherited his mother’s disposition to die by his own hands: he hung himself.

One dramatic recent finding revealed an anatomical warning sign of severe depression—and thus of a future desire to die. Last year psychiatrist Bradley Peterson of the Columbia College of Physicians and Surgeons and the New York State Psychiatric Institute and his colleagues reported having found a 28 percent thinning, on average, of the brain’s cerebral cortex in the right hemisphere among 66 people from families with major depression as compared with 65 people from families without it, as assessed by magnetic resonance imaging. More than half the offspring of people with major depression had this structural feature, starting as young as age six.

The thinner cortex may increase the risk of developing depression by disrupting a person’s ability to pay attention to and interpret social and emotional cues from other people. “The thinner the cortex in the right hemisphere, the more the people struggled with cognitive problems such as attention and memory for social stimuli,” Peterson says. He theorizes that being born into a family with depression produces this cortical thinning—whether from genetics or environmental influences, he is not certain—and that thinning, in turn, leads to problems with processing social stimuli, interpersonal difficulties, depression and, all too often, suicide.

Interpersonal problems are a common precipitating event in suicide. Last August, for example, George Sodini, a 48-year-old Pennsylvania man, killed three people at a fitness club and then himself. On his Web page, he complained about years of rejection by women. “Women just don’t like me,” wrote Sodini, who also noted that he had not had sex for 19 years.

Deadly Experience
In the past few years researchers have looked beyond mental illness, personal problems and other motivations for wanting to die as clues to the causes of suicide. Major depression is the strongest predictor of suicidal thoughts—but not of who actually “makes an attempt,” says psychologist Matthew Nock of Harvard. Suicide scientists are now investigating the triggers for the actions that lead to death itself: What causes people to go through with hurting themselves?

In 2000 a Florida inmate, John Blackwelder, incarcerated for pedophilia, wanted to kill himself but was too scared to do it. Instead, he told reporters, he strangled fellow inmate Raymond Wigley, a convicted killer, to try to get on death row. His strategy worked: on May 26, 2004, the state of Florida executed Blackwelder, then age 49, by lethal injection. “He wanted to die by suicide, but he couldn’t do it himself, so he forced the state of Florida to do it,” Joiner explains.

The missing ingredient in his case, as in many others: fearlessness. Anyone too timid to intentionally hurt himself or herself is not at serious risk of completing a suicide attempt no matter how eager to die he or she might be. What makes some people brave enough to be at risk? One answer is experience. “Past experience of any sort that will get you used to pain or injury or death has the potential to make you more and more fearless,” Joiner says. Such hazardous, frightening—and emboldening—practices include intravenous drug use, nonsuicidal self-injury and unsuccessful suicide attempts.

In particular, repeated exposure to the idea of ending your own life makes you grow more comfortable with the thought. In a 2008 summary of a study that was published in the Journal of Consulting and Clinical Psychology, Joiner and his colleagues wrote: “Engaging in painful and provocative experiences, including past suicide attempts, increases an individual’s acquired capability for self-harm.”

Practice with other forms of self-injury may similarly prepare a person for suicide. In a paper that appeared in the fall of 2008, researchers at the Centre Hospitalier de Sainte Anne in Paris analyzed 26 years’ worth of literature on suicide, self-mutilation (cutting, bruising, burning, biting, head-banging) and borderline personality disorder (BPD—a psychiatric diagnosis characterized by unstable moods, relationships and behavior) to investigate the link, if any, between self-mutilation and suicide. They reported that more than half of people with BPD deliberately mutilate themselves and that 5 to 10 percent of BPD patients die by suicide, a rate about 400 times higher than that of the general population. The results hint that self-mutilation, especially in the context of BPD, is a risk factor for suicide. The reasons for this connection, the authors wrote, may include increased aggression among those who self-mutilate, combined with a tendency to underestimate the lethality of their behavior.

Indeed, a blasé attitude toward pain and injury can be deadly even if a person does not mean to kill himself or herself. Most people who cut themselves are not suicidal but, ironically, are trying to make themselves feel better, according to Brown University psychologist Shirley Yen. In some cases, the physical pain may provide relief from a feeling of numbness; in others, it staves off emotional pain, Yen explains. But then cutters may occasionally push the envelope—making more or deeper incisions—because they have grown accustomed to feeling injured—and may underestimate the risk of death. Such behavior can sometimes end in tragedy.

Putting Up with Pain
A person may also become used to pain and injury because of violent mistreatment from others. In a retrospective study published in 2007, Joiner and his colleagues analyzed National Comorbidity Survey data and found indications that childhood physical and violent sexual abuse should be seen as greater risk factors for future suicide attempts than nonviolent, sexual molestation and verbal abuse. Referring to Joiner’s work, Harvard’s Nock says, “People who have been abused or have abused themselves would habituate to the experiences of pain and acquire the ability to act on suicidal thoughts.”

Some of this experience may even become etched in the brain. In a 2009 study geneticist Moshe Szyf of McGill University and his colleagues showed that childhood abuse appears to produce specific patterns of so-called epigenetic marks on the DNA of brain cells in people who later killed themselves [see “The New Genetics of Mental Illness,” by Edmund S. Higgins; Scientific American Mind, June/July 2008]. Such studies highlight a biological connection between experience with abuse and suicide, although whether those epigenetic changes underlie depression or daring, or both, is unknown.

Some people acquire the fortitude to kill themselves by habituating to other forms of discomfort. Anorexics are at higher risk of suicide than people with healthy eating habits, perhaps because of their ability to withstand pain from hunger (and, in many cases, from cutting themselves as well). In a 2008 study of nine case reports of anorexics who died through suicide, Joiner and his co-authors concluded that “individuals with anorexia nervosa may habituate to the experience of pain during the course of their illness and accordingly die by suicide using methods that are highly lethal.” One anorexic entered a public rest­room at a gas station, stuffed towels in vents and under the door, set a trash can on fire—and died of carbon monoxide poisoning before she was found two hours later, according to a 2008 report in the Journal of Affective Disorders.

The danger may extend to other eating disorders, which are also, of course, associated with depression. People with eating disorders are 23 times as likely to die by suicide than people who eat normally—a statistic that makes eating disorders a better predictor than depression of death by suicide, says sociologist Steven Stack of Wayne State University.

A higher tolerance for pain may also partly explain why men are more likely than women to succeed in killing themselves [see “I Do Not Feel Your Pain,” by Ingrid Wickelgren; Scientific American Mind, September/October 2009]. Along with a greater determination to die, a hardiness to hurt may lead men to the most lethal methods. Men prefer guns to pills, studies show, and last February researchers reported that men are more likely to shoot themselves in the head than women are. (In an investigation of the 807 firearm suicides in Wayne County, Michigan, that occurred between 1997 and 2005, Stack and his colleagues found that women were just half as likely as men to shoot themselves in the head.) The prospect of pain and disfigurement, along with a weaker will to die among women, may make females less apt to reach for such surefire weapons.

Impulsivity—which also tends to characterize men more than it does women—exacerbates the problem. After all, a release of inhibitions makes going through with plans to kill yourself easier. A major contributor to the loss of impulse control is the abuse of substances, such as alcohol, that are known to have this effect. Alcohol abuse is associated with higher rates of suicide. In fact, according to a 2003 study in the American Journal of Psychiatry, 4.5 percent of alcoholics attempt suicide within five years of their diagnosis of alcoholism. Other studies have found that nearly 40 percent of patients who seek treatment for alcohol abuse report having attempted suicide—a rate sixfold to 10-fold higher than that in the general population. “They use alcohol as the lubricant that allows them to take action,” says Marvin Seppala, chief medical officer at Hazelden, a nonprofit addiction treatment program with facilities in Minnesota, Oregon, Illinois and New York State.

Having an impulsive personality might also help mentally prepare you to take your own life. “If you’re impulsive, you will find yourself in a lot of painful and provocative situations,” Joiner says. “These, in turn, habituate you to pain and fear, and so then if you develop the desire for death, you’re not afraid to act on it.” (The resulting suicides, however, are not impulsive but planned, he notes.)

Of course, impulsivity is just part of the equation—and, some say, a small part. In 2009 Brown University researchers reported that people who scored high in negative emotions such as anxiety, anger, fear and stress were more likely to try to kill themselves than people who scored high in impulsivity. Nevertheless, impulsivity might well act in concert with these other qualities to raise a person’s risk.

Removing the Will and the Way
Because both a motivation to die and the daring to act on it are necessary ingredients of suicide, preventing this terrible ending, experts say, means combating both these elements. The federal government wants to start young on the first factor. In 2009 the Substance Abuse and Mental Health Services Administration started Project LAUNCH (Linking Actions for Unmet Needs in Children’s Health) to promote the physical, emotional, social and behavioral health of kids from birth to age eight. The program aims to promote psychological well-being of children, whether or not they suffer from depression, by targeting at-risk kids.

As a way of identifying kids most likely to develop depression, Peterson’s team at Columbia University is using the thinning of the brain’s right cerebral cortex as an early diagnostic marker in families with a history of the illness. “There is no other test for people other than being born into a family with depression,” Peterson says. If an individual bears this brain feature, he adds, the person has an 80 percent chance of developing depression in his or her lifetime. Those people, then, might receive preventive drug treatment or psychotherapy.

Training health care professionals is also important for averting depression-induced suicides. In Nuremberg, Germany, a group reduced suicide attempts simply by educating primary care physicians about depression and encouraging them to get suicidal people straight to the emergency room. Many experts also recommend training addiction specialists in suicide, given that addiction problems boost a person’s chances of killing himself or herself.

For similar reasons, young people with, or at risk of, eating disorders also need suicide-specific therapy. Correcting the distorted body images that commonly plague adolescent girls would go a long way toward preventing the sickness that leads to suicide, says Dhaval Dave, an expert in health economics and risky behavior at Bentley University and research fellow at the National Bureau of Economic Research. In addition, the one quarter of patients with eating disorders who engage in self-mutilation need to be warned that they may end up killing themselves—by accident.

Other measures discourage suicide attempts without affecting a person’s desire to live. Laws that restrict the availability of alcohol appear to result in lower suicide rates. In a 2009 study in the American Journal of Public Health, Indiana University researcher William Pride­more and his colleagues found a significant decrease in suicides among men and women in Slovenia after a new national policy limited when and where alcohol could be sold and set the minimum drinking age at 18.

Making suicide more difficult to accomplish—say, by reducing access to so-called lethal means—can also curb its frequency. In a 2007 review psychiatrists in Copenhagen found that restricted access to firearms, domestic gas, car exhaust and barbiturates was associated with a decline in suicide rates. After the U.K. passed legislation in 1998 to reduce the number of acetaminophen tablets per package to a maximum of 16 in general stores and 32 in pharmacies, lethal poisonings from an overdose of the over-the-counter medication decreased.

Physical obstacles to suicide can also lessen its frequency. When a net went up under the Golden Gate Bridge, people could not jump to their deaths. Most did not switch to another suicide method, either. “Most people do not go for a plan B,” says psychologist Mark Reinecke of Northwestern University. Adding smelly chemicals to odorless natural gas in the U.S. discouraged people from inhaling a lethal dose of it. When Britain changed its gas supply from toxic coal gas, the most common method used for suicide during the early 1960s, to nontoxic North Sea gas, its suicide rate dropped, according to an April 2009 review in the Lancet.

Such measures are important given the impossibility of identifying, and thwarting, every person in danger of taking his or her own life. “We have not been very good about predicting suicide or suicide attempts,” says Yen, although a scientific working group has come up with a list of warning signs.

Hernandez never wants to see any of those signs in her daughter, Serenity. Once a week she and one-year-old Serenity attend a child-parent psychotherapy group; they also go to the Healthy Steps program at the Children’s Hospital at Montefiore in New York City, which aims to prevent mental disorders in high-risk families, starting very early in life. “We get babies referred to us at two days old,” says psychologist Rahil Briggs, who directs the program. “It’s prevention, prevention, prevention.”