The following is an updated version of this article, published in 2019.

Imagine a doctor who wanted to treat a broken leg with chemotherapy. Or treat cancer with a cast.

Just because cancer and broken legs are both things that happen to the body doesn’t mean they call for the same treatment. These are the kinds of issues policymakers face every day. Take gun violence. It feels like one big problem, but it’s actually a bunch of different problems that don’t necessarily have a single cause. But it’s also easy to get so focused on the differences between types of gun violence that we miss the unexpected connections. Just like a fragile, cracked bone could be a symptom of certain kinds of cancers, researchers are finding evidence that suicides and mass shootings can often be different expressions of the same problem.

I first reported on this connection back in 2019, as part of trying to explain why a suicide prevention tool — “red flag laws” that enable family members and law enforcement to determine that a person is a threat to themselves or others and temporarily remove guns from their home — was being proposed as a way to prevent mass shootings. 

Today, 19 states have enacted red flag laws and they’ve had mixed results in violence prevention. But the connections between suicidality and mass shootings have just gotten stronger. “Many of these mass shootings are angry suicides,”  James Densley, professor of criminal justice at Minnesota’s Metropolitan State University, told me four years ago. And now there’s even more evidence to suggest that’s true. 

It isn’t news that a lot of mass shooters suffer from suicidal ideation, said James Lankford, a professor of criminology at the University of Alabama. But it wasn’t until he published a 2021 study comparing mass shooters to other demographic groups that he truly realized just how much more mass shooters had in common with people who die by suicide than they did with other kinds of homicide offenders.

“Homicides are rarely premeditated but public mass shootings almost always are,” Lankford said. So are suicides. While mass shootings were 3.8 times more likely to be premeditated than standard homicides, they were only 1.2 times more likely to premeditated compared to suicide. Mass shooters were more likely than other homicide offenders to act alone. They were more likely to be killed by law enforcement. And while standard homicide offenders aren’t particularly likely to experience suicidal tendencies, in Lankford’s study anyway, mass shooters were a bit more likely to have a history of suicidal ideation than even people who actually died by suicide. 

Lankford is not the first person to find connections between suicide and mass shootings. In a database of more than 150 mass shootings that took place between 1966 and 2018, Densley found that about half the attackers in his sample had demonstrated signs of feeling suicidal before they hurt others. A different set of researchers who analyzed 41 school shooters for the Secret Service and Department of Education found that 78 percent had a history of thinking about or attempting suicide.

“We’ve even talked to a couple of people who tried to kill themselves but failed and then launched an attack because they were hoping police would kill them,” said Marisa Randazzo, a former chief psychologist for the Secret Service who now consults on active threat assessment with schools and other organizations, told me.

A third set of researchers, who compiled the details of 119 lone-actor terrorists, did not specifically track whether the people in their data set had thought about or attempted suicide, but the researchers told me they also found significant overlap between mass shootings and choices that suggested suicidal tendencies. “A fairly sizeable subset only planned this to be a one-off event” — that is, something they didn’t return from — said Paul Gill, a professor of security and crime science at University College London and the researcher in charge of that data set. “They were taking preparations to maximize the chances of death by cop or their own hand.”

In other words, acts of mass violence are functioning as a method of suicide. “These are individuals who are planning in advance to commit a crime for which there’s almost no chance they’ll avoid life imprisonment or death as a direct result of the crime,” Lankford said. “It’s very reasonable to say that they’re not very invested in their current lives, or their future lives.” 

That fact has implications for policy and prevention. 

A connection to suicide means armed guards are unlikely to be a deterrent to mass shooters, Densley said. In 2021, he published a paper that analyzed 133 cases of school shootings between 1980 and 2018 and found that the ones where armed guards were present had a death rate 2.8 times higher than those with no armed guards on scene. Densley thinks this could partly be because in the eyes of a shooter exhibiting suicidal ideation, good guys with guns are a feature, not a bug. They may see a higher chance of death for themselves and they may go in more heavily armed — and more innocent people could be caught in the ensuing shootouts. And even if that’s not the case, Lankford said, a shooter having armed guards to fight creates a story that increases the killer’s chances of achieving notoriety and fame.

The connection to suicide also means potential mass shooters can easily slip under the radar of law enforcement, who are trained to deal with crime, not crisis, Lankford said. It’s not uncommon for future mass shooters to come to the attention of law enforcement before their major attack, but those interactions often go nowhere because that person has no connection to violent crime or gangs, and they have no previous criminal record. “Those questions aren’t useful in assessing the threat of a mass shooter,” he told me. 

And these kinds of shooters remain difficult to profile. Even knowing the connection to suicidality doesn’t particularly help because most suicidal people aren’t a danger to others, just themselves. 

But there is some good news here. Mass shootings are very often preceded by what experts describe as cries for help — shooters tell other people about their plans, they make threats, they describe their desire to kill and be killed. In a 2021 study of 170 perpetrators of mass shootings, researchers found that 44 percent had leaked specific details of their own plans beforehand. Multiple studies have found that family and friends of a mass shooter are often aware that something is wrong long before the violence happens. That happened one-third of the time in Densley’s database, 64 percent in Gill’s, and 81 percent in the cases Randazzo logged.

And this is why many experts who study the epidemiology of mass shooters like the idea of red flag laws as a preventative. Even once you identify some details that many of the attackers have in common, such a large swath of the population shares these traits that the “profile” is fairly useless for prevention. Red flag laws circumvent that problem by focusing less on a type of person and more on a type of emotional and situational crisis — where the people involved aren’t necessarily “bad guys” but troubled individuals in need of help. Gill thinks of it as a public health approach, analogous to the way we treat physical health problems that are hard to profile.

“We know that raised cholesterol leads to heart problems. We don’t have the ability to predict who in the general population who already has raised cholesterol will go on to have a heart attack. So we put in place prevention policies to try to decrease cholesterol in the whole ‘at risk’ community,” he said.

For the researchers who study mass violence, what’s appealing about red flag laws is that these rules have the potential to shift the emphasis from a cut-and-dried checklist of dangerous traits to a more nuanced system that accounts for a person’s big-picture emotional state. 

Right now, experts said, even when friends, family and teachers know something is wrong with a potential shooter, they may not be able to actually do much about it. Sometimes people don’t know who to tell. Sometimes they choose not to tell in order to avoid sending a loved one to prison for crimes they haven’t yet committed. Sometimes the authorities can’t do anything because the nature of the threat doesn’t include illegal behavior.

All these researchers supported red flag laws because they could create a clear plan of action for friends and family concerned about a loved one’s combination of emotional crisis and violent threats. It creates a place to take concerns, a system to evaluate those concerns and a means of mitigating them. That’s particularly true, researchers said, if national red flag laws are set up so that the system isn’t punitive. Ideally, the process would focus on helping a person get through to the other side of an emotional crisis rather than putting them in jail. It’s also important, the researchers said, to make sure the laws are focused on professional evaluations of overall behavior, not checklists.

And there’s some evidence this could work. An analysis of records from California, where one of the first red flag laws was enacted in 2016, found at least 21 cases where the laws had been used specifically because people around a person were worried about their potential to commit a mass shooting. As of 2019, none of those people had followed through on that potential. It’s impossible to know, however, how those risks would have played out if the red flag hadn’t been there. 

But if those parts work together the way they should, then red flag laws really could be a useful tool for combating the segment of mass shootings that function like very public, violent suicides. “There’s an important piece when we interviewed school shooters and active threat cases,” Randazzo said. “They feel very strongly about two things: They have to carry out the violence, they have no options left, but they also don’t want to do it and hope someone will stop them.”