Although personal protection is often cited as a motive for firearm ownership, self-defense homicides accounted for far fewer firearm-related deaths than accidental deaths and suicides in Washington state's King County, which includes Seattle and many of its suburbs.

For each case of self-defense homicide to occur in the home from 2011 to 2018, there were 44.1 suicides (95% CI 24.9-78.1), 7.3 criminal homicides (95% CI 4.0-13.3), and 0.9 unintentional deaths (95% CI 0.4-2.1), reported Elissa K. Butler, MD, of the University of Washington in Seattle, and colleagues.

Across the 7-year period, the incidence rate of firearm deaths was 3.9 per 100,000 person-years, the team wrote in a research letter published in JAMA Internal Medicine.

"This can encourage physicians to counsel their patients' thinking about owning a firearm or already owning one that their firearms may not be keeping them safe," Butler told MedPage Today. "They should be concerned it may actually increase their risk of suicide and homicide, and not actually protect them."

The study did have important limitations, however: it did not include nonfatal firearm injuries or cases in which firearms were used as deterrents without being fired, and it was conducted in a single urban county, Butler and colleagues noted.

In King County, about 340,000 adults reported a firearm in their home in 2015, with 150,000 reporting that they store them unlocked. In that year, firearm fatalities cost the government almost $200 million in medical costs and lost productivity.

The findings mirror a prior study published in 1986 in the same county that found the vast majority of firearm deaths involved suicides and homicides, whereas just 1.8% of firearm-related deaths were in self-defense.

This, in itself, is "a sad commentary on the lack of progress," commented Jerome P. Kassirer, MD, of Tufts University School of Medicine in Boston, in an accompanying editorial.

However, "all is not lost," and evidence shows that more comprehensive firearm legislation at the state level yields lower firearm-related injuries, he wrote, citing Massachusetts as a "case in point."

There, individuals must obtain a license to carry, pay a $100 fee, provide identifiable information and be subjected to a background check, and take a gun safety course. Firearms purchased must be registered and stored with a trigger lock or in a safe. And the entire process is monitored by local police who can at any point reject an application due to the risk an individual poses as a danger to society.

Washington is an "open carry" state, but obtaining a firearm requires a license, background check, and proof that the purchaser has completed a firearm safety training program. The state also has punitive measures in place for storing firearms in an unsafe location or without a trigger lock or similar device.

Massachusetts has the strictest firearm laws and the lowest number of gun-related deaths in the country, but many other states lack these restrictive policies, Kassirer said.

"It has become much too easy in a moment of anger or depression to grab a loaded weapon in a desk drawer and kill someone or ourselves," Kassirer noted.

For their study, Butler and co-authors linked records from the county medical examiner's office to the Washington office of the state homicide investigation tracking system to determine how many firearm-related deaths occurred. The team included all firearm deaths occurring in homes and excluded deaths in which individuals were shot by police.

In total, 647 firearm deaths were recorded in 2011-2018, including 529 suicides, 99 homicides (of which 12 were self-defense), 11 unintentional deaths, and eight of an undetermined cause.

Men comprised a greater portion of deaths by firearms than women (83.6%), and non-Hispanic white individuals also disproportionately died. The median age of death was 48.

Most deaths occurred in the firearm owner's residence, including suicides (502 of 529), homicides (57 of 99), and accidental deaths (seven of eight), the researchers reported.

They noted that while most suicides involved guns kept in the home (93.4%), most homicides involved guns brought to the home (81.3%).

If you or someone you know is considering suicide, call the National Suicide Prevention Hotline at 1-800-273-8255.