The last year has shined a harsh light on two distressing realities of American life. Mass shootings are becoming more common. And more Americans are killing themselves. These disturbing trends share something in common, obvious in the first case and less so in the second: guns.

In the past three months, America experienced the worst mass shooting in modern U.S. history, with 49 people killed in Orlando, and new data showed that suicide rates have reached a three-decade high. Although mass shootings get most of the attention, experts say that the growing suicide rate reveals the much bigger effect of widespread firearm availability in the United States — and claims thousands more lives.

In 2014, 42,773 Americans killed themselves according to the Centers for Disease Control and Prevention. Half did so with guns. That’s not only more than the number of Americans who were killed in mass shootings, it’s more than the number of people who were killed with guns in homicides and accidents combined.

The fast-rising U.S. suicide rate is in sharp contrast to what's happening in most other developed countries, where suicide rates have declined significantly over the past decade.

PCT CHANGE IN SUICIDE RATE SINCE 2000, AGE-ADJUSTED United States 20% +17% 10 United Kingdom 0 Canada -10 Australia France -20 2000 2006 2012 PERCENT CHANGE IN SUICIDE RATE SINCE 2000, AGE-ADJUSTED 20% United States +17% 10 0 United Kingdom Canada Australia -10 France -20 2000 2004 2008 2012

These figures are age-adjusted, meaning they account for how many people are at especially suicide-prone ages.

Separating out the role of guns in facilitating these suicides, in relation to an array of psychological and cultural factors, is difficult. One way to estimate the impact, according to experts on guns and suicide, is to analyze the U.S. suicide rate in comparison with similar countries.

Nobody knows what would happen if firearm availability in the United States resembled levels of other developed countries. But there’s widespread agreement among experts that the suicide rate would decline significantly. To illustrate this point, we calculated what would happen to the U.S. suicide rate if the percentage of suicides involving firearms were similar to that of four other Western countries (Australia, Canada, France and Britain) for which data is available.

Fifty percent of Americans who commit suicide do so with a gun. In our hypothetical, we assume that figure is just 9 percent — the average level of those four other Western countries. We then assumed the remaining 41 percent would try to commit suicide by other methods, such as suffocation or poisoning. Because none of these methods is as lethal as a gun, fewer people would succeed at committing suicide than if they used firearms. Of course, in reality, it’s possible some people in this 41 percent would not attempt suicide otherwise; we assume they all do to keep our estimate conservative.

We calculate that the total suicide rate would decline by 20 to 38 percent, depending on the alternative methods used. (You can read more about our methodology, which was endorsed by three top suicide and guns experts.)

= 50 SUICIDES The U.S. in 2014 If the U.S. were like other countries About 30,000 suicides 42,773 suicides Firearm suicides could decrease by 82 percent. Suicides overall could decrease by 20 to 38 percent. If the U.S. were like other countries The U.S. in 2014 = 50 SUICIDES About 30,000 suicides 42,773 suicides Firearm suicides could decrease by 82 percent. Suicides overall could decrease by 20 to 38 percent.

“If we had a shift in the number of people who attempt to end their life with a firearm — who chose other means — we would very greatly reduce our suicide rate,” according to Daniel Webster, a professor at the Johns Hopkins Bloomberg School of Public Health.

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And for those who did not die, it's likely they would not try to commit suicide again. A 2002 review of 90 studies indicates that more than 90 percent of people who survive a suicide attempt won’t die from a later suicide attempt either.

The lethality of guns

The wide availability of guns in America matters for suicide because guns are more lethal than any other suicide method. According to CDC data, which includes suicide attempts that were serious enough that the person ended up in the emergency room or dead, 90 percent of people who shoot themselves die, but only 4 percent of people who poison themselves die. Other common suicide methods fall between these: 81 percent of people who attempt to suffocate themselves die and 32 percent of those who jump from significant heights are killed. Overall, 11 percent of all people who attempt suicide — and get far enough to end up in an emergency room and thus in the CDC’s data — die.

Experts contend if you reduce a suicidal person’s access to firearms, it’s likely to save his life, even if he attempts suicide with a different method.

This goes beyond the inherent lethality of the method; the time it takes to execute a suicide attempt plays a huge role in survival. With a gunshot, death is often instant. With an overdose, it can take hours for a person to die, creating more opportunities for a person to call for help or for someone to intervene.

“Anything that builds in delay is working in your favor because that fever-pitch time when you’re actually willing to swallow the poison or pull the trigger is often fairly narrow,” said Cathy Barber, who directs a suicide-reduction campaign at the Harvard School of Public Health.

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The greater lethality of firearm suicides is apparent in the significant gap between male and female suicides. Men are much more likely to choose to use a gun, whereas women are much more likely to poison themselves. The result: Women attempt suicide 50 percent more often than men yet die from it a third as often.

The graphic below shows the breakdown among five common suicide methods for each gender. Men use guns in 16 percent of attempts, leading to 55 percent of male fatalities. Women use guns in only 2 percent of attempts and make up 31 percent of female fatalities.

Percent of men and women who attempt self-harm or commit suicide, by method MEN WOMEN

The spiking suicide rate

The rising suicide rate over the past 15 years is mainly driven by a growing death toll among white Americans. According to CDC data, between 1999 and 2014, the suicide rate among whites rose 42 percent. The rate has grown much faster among women than men, but because men commit suicide more often than women, their suicides still made up 69 percent of the increase.

Firearm suicides increased 28 percent between 1999 and 2014 and accounted for 39 percent of the overall increase in such deaths. Other methods have increased across the board, too. Over the 15 years, the suffocation rate more than doubled, accounting for 42 percent of the total increase in suicides. Several experts were unable to name the reason behind the increasing frequency of suffocations.

U.S. SUICIDES (POPULATION ADJUSTED) Controlling for population growth, about 10,000 more people died by suicide in 2014 than in 1999. 10,000 20,000 30,000 1999 2014 39 percent 42 percent 13 percent by firearm by suffocation by poisoning U.S. SUICIDES (POPULATION ADJUSTED) 10,000 20,000 30,000 1999 2014 Controlling for population growth, about 10,000 more people died by suicide in 2014 than in 1999. 39 percent 42 percent 13 percent by firearm by suffocation by poisoning

Gun access is a risk factor for suicide

Research shows that the longer it takes someone to obtain a weapon — such as if they have to go out and buy one or if the state has a mandatory waiting period — the more likely they are to decide against killing themselves or choose an alternative, less lethal method.

“If you have an impulse for suicide and you have easy access to a gun, you’re very likely to be successful at committing suicide. But if access to that means is not there, then the impulse may pass,” said E. Michael Lewiecki, a professor at the University of New Mexico School of Medicine who has researched suicide and public policy.

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One 2006 study found that from the 1980s to the 2000s, every 10 percent decline in gun ownership in a census region accompanied a 2.5 percent drop in suicide rates. There are numerous other studies that show similar results.

This pattern becomes clear when looking state by state. The states that have higher rates of gun ownership, where people have more access to guns, also have higher rates of suicide. Suicides are twice as common in states with high gun ownership than those with low gun ownership, even after controlling for rates of mental illness and other factors, according to a 2007 study.

Gun Ownership Rate 5.2% Suicide rate per 100,000 5.8

The pattern is clear in other countries, too.

In 2006, the Israeli military enacted a policy preventing soldiers from taking their weapons home from the base on the weekends. Suicides among soldiers younger than 24 decreased by 40 percent.

In Australia in the late 1980s and early 1990s, the government implemented a series of laws in an effort to reduce access to the most lethal methods of suicide, such as a gun buy-back program and regulations on cars making it harder to get a lethal dose of carbon monoxide. By the late 2000s, the suicide rate dropped nearly 40 percent.

How government policy fits in

It’s difficult to know, of course, exactly how much gun-control measures could decrease access to guns and therefore divert suicidal Americans to less lethal methods.

In a political climate where gun-control measures targeting criminals and suspected terrorists are contested, it’s hard to imagine legislators jumping at the chance to take guns away from, for instance, Americans who live with a severely depressed family member. Especially because the highest gun-access and the highest suicide rates tend to be in states with Republican-controlled legislatures. Even if legislators were prepared to reduce gun access, identifying at-risk individuals is challenging.

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States across the country have programs focused on educating people, especially mental-health professionals and parents, about the risks of firearm suicides. Some government organizations have programs distributing trigger locks to gun owners. More recently, some states have allowed judges to begin issuing “gun violence restraining orders.” With these, individuals can go to civil court to get a gun temporarily confiscated from an owner who is a threat to himself or others.

Many states have also implemented measures to keep guns away from teenagers, for whom suicide is the third most common cause of death. Minimum age requirements for purchasing weapons or requiring gun locks when children live in the house can have a significant impact. A 2004 study found that in the 18 states that introduced the gun locks rule, there was an 8.3 percent decline in teen suicides.

Garden-variety gun-licensing laws can also have an effect, Webster said. Not only does obtaining a permit create a possibly life-saving delay, but “some of the same risk factors for criminal action are the same risk factors for suicide — substance abuse, impulsive behavior, aggressive behavior, frankly being male.” So the permitting process may weed out suicidal individuals.

But all of these laws make it more difficult for Americans without criminal records or suicidal thoughts to purchase arms, which makes them highly unpopular with gun rights advocates.

These laws are wrongfully “assuming guns actually contribute to suicide,” according to John Lott, president of the Crime Prevention Research Center, which advocates for gun rights. In his view, they aren’t a factor in the suicide rate, citing a survey by the right-leaning Cato Institute. He argues that, in the absence of guns, people will instead choose a different suicide method and carry it through to completion. In Lott’s view, these gun restrictions actually increase the total death toll, as they don’t decrease suicide rates but leave people unarmed against violent intruders.

“It’s just common sense that if someone can go to a store and buy a gun and get some ammunition and take it home in the next 20 minutes, that guy can go shoot himself," Lewiecki said. "It’s so easy to get that lethal weapon.”

You can read about the methodology behind this piece here.