People look at handguns and other items during The Nation's Gun Show at the Dulles Expo Center in Chantilly, Va., on Oct. 3. (Jabin Botsford/The Washington Post)

Few topics stir more controversy in this country than guns. Mass shootings and urban gun violence inflame public passions. Gun control measures divide our political leaders, and elections often hinge on candidates' views of guns.

I struggle with issues related to firearms every day, but in a different way. To me, it's not about politics or elections. It's part of my daily job. As a mental health provider, I have to ask all my patients about guns.

I spend many of my days and nights caring for patients with psychiatric crises in emergency departments. We address a variety of clinical problems, from hallucinations to delusions to addiction. Suicidality is one of the more common ones. Too often, patients want to hurt themselves or have already tried to do so.

So why do I ask about guns?

Because when I think about how patients might harm themselves, guns frighten me the most. As a resident physician in psychiatry, I see some pretty terrible things. Suicidal patients talk about hanging themselves, overdosing, throwing themselves into traffic, and a host of other awful ways to end their lives.

But when I hear that a patient owns a gun, it gives me extra pause.

No, I'm not creating a registry. No, I don't care if they're members of the National Rifle Association. I don't claim to know the right balance between gun control and personal freedom. I just want my patients to be safe.

When it comes to suicide, guns matter. In a column published by Newsweek last year, writer Mike Mariani sums up why:

"The problem is that firearms are frighteningly lethal. The most common method of attempting suicide, overdosing on drugs, has a completion rate of just 3 percent (in other words, 97 percent of attempters survive). Gun suicide, by comparison, has a completion rate of 85 percent. This is surely gun violence at its most virulent — Berettas and Glock 17s crystallizing passing impulses into something horrifically permanent. ..."

Research further supports this link. A 2007 study found states with the highest household gun ownership have roughly double the number of suicides compared with states with the fewest household guns. While gun owners are no more likely to have mental health issues than those without guns, access to a gun means acting out on suicidal thoughts has more deadly consequences. As written in a 2008 article in the New England Journal of Medicine, "a suicide attempt with a firearm rarely affords a second chance."

Suicide risk isn't the only reason I ask about guns. Sometimes, patients threaten to harm other people as well. In these circumstances, we have to assess the seriousness of these statements and risk factors for violence, including access to weapons.

In the media, mental illness is a common scapegoat for gun violence. But the reality isn't that simple. In a column for the Atlantic earlier this year, writer Julie Beck points out "the overwhelming majority of people with mental illnesses are not violent, just like the overwhelming majority of all people are not violent." Actually, a 2005 study found adults with severe mental illness are more than 11 times more likely to be victims of violence than adults in the general population.

Indeed the specter of suicide, rather than homicide, haunts me most often in my daily work. Each year in the United States, there are nearly twice as many suicides by guns than homicides by guns, according to the Centers for Disease Control and Prevention. Yet public perceptions of gun violence rarely associate with a person alone at home, desperate, in need of medical help.

So if my colleagues and I evaluate a patient who owns a gun and wants to self-harm, or more rarely harm others, what do we do?

We can pursue a range of options, from handing out gun locks to requesting family or friends temporarily hold onto firearms to asking that local police to perform a welfare check at the patient's home. In extreme cases, if patients pose an imminent risk to themselves or others because of mental illness, we can place them on a legal hold to evaluate them in the hospital for up to 72 hours.

These approaches hinge on the concept of lethal means reduction. By temporarily limiting patients' access to guns and other dangerous instruments, like sharp objects or pills, we hope to protect them from transitory suicidal or homicidal impulses. A large body of research supports the efficacy of these prevention measures, particularly in reducing rates of suicide.

Unfortunately, the politics of guns sometimes affect patient care. In 2011, lawmakers in Florida passed a law to curtail physicians from talking to patients about guns, and similar bills have popped up in states from North Carolina to Oklahoma to Minnesota. Over the last two decades, Congress has virtually blocked the Centers for Disease Control and Prevention from conducting research into gun violence in the United States.

This is too bad because, as health-care providers, we do our best to help patients with evidence-based practices. We're not out to get anyone's guns. We don't wake up hoping to infringe on patients' personal lives. But, to keep patients and communities healthy, clinicians need to be able to ask about firearms.

In medicine, rarely can a single question make such a difference.

Nathaniel P. Morris is a resident physician in psychiatry at the Stanford University School of Medicine.

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