After a shooting, once the dust has settled, and the initial shock and panic has abated somewhat, fearful minds begin to cast about for explanations. Given the frequency with which gun deaths occur in the United States, “Why did this happen?” and “Who could do something like this?” are questions the country faces with grim regularity.

Unfortunately, a consistent and dangerous narrative has emerged—an explanation all-too-readily at hand when a mass shooting or other violent tragedy occurs: The perpetrator must have been mentally ill.

“We have a strong responsibility as researchers who study mental illness to try to debunk that myth,” says Jeffrey Swanson, a professor of psychiatry at Duke University. “I say as loudly and as strongly and as frequently as I can, that mental illness is not a very big part of the problem of gun violence in the United States.”

The overwhelming majority of people with mental illnesses are not violent, just like the overwhelming majority of all people are not violent. Only 4 percent of the violence—not just gun violence, but any kind—in the United States is attributable to schizophrenia, bipolar disorder, or depression (the three most-cited mental illnesses in conjunction with violence). In other words, 96 percent of the violence in America has nothing to do with mental illness.

A study from 1998 that followed patients released from psychiatric hospitals found that they were no more prone to violence than other people in their communities—unless they also had a substance abuse problem. So mental illness alone was not a risk factor for violence in this study.

Those are the facts. But cultural narratives are often more powerful than facts, and that 4 percent gets overblown in people’s minds.

A new study published in Health Affairs shows how the news perpetuates this narrative, with a look at how several prominent newspapers and broadcast networks covered mental illness from 1995 to 2014. More than half of the stories they looked at during that period—55 percent—mentioned violence in conjunction with mental illness. That proportion was pretty much consistent across the 19 years. But stories connecting mental illness with mass shootings specifically increased from 9 percent between 1994 and 2004 to 22 percent between 2005 and 2014.

Perhaps this can be partially attributed to high-profile shootings like the Tucson shooting in 2011, in which the killer did have schizophrenia. “That’s an event that is newsworthy, but the fact that it was linked to mental illness is not representative of most people who have schizophrenia, or most violence,” says Emma McGinty, the lead author on the study and a professor of health policy at Johns Hopkins University. “[And yet] that link pervades the public psyche.”

It pervades so much so that people speculate about killers’ mental states, even in the absence of any evidence that they were living with any disorder. For example, in an article about the gunman who recently killed a professor at the University of California, Los Angeles, New York magazine writes: “Police do not know for sure yet if Sarkar had a history of mental illness.” Why does this particular absence of information bear mentioning? It seems mental illness is so linked to gun violence in people’s minds that we have to address it even when it’s not there.

And when there is evidence that a killer also happened to have a mental illness—like the pilot who crashed a Germanwings plane in 2015, who had a history of depression—the media seize upon it like a bear trap. “We’ve got it now! This is what was wrong with him,” is the message portrayed.

This is a really tricky needle to thread, because something was clearly wrong with him. Of course someone who is perfectly healthy and well-adjusted in every way would not go out and kill a bunch of people.

“This is one of the hardest distinctions to make,” McGinty says. “Anyone who kills someone else in a mass shooting scenario or otherwise is not what we would consider mentally healthy. But that does not mean they have a clinical diagnosis and therefore a treatable mental illness. There could be emotional regulation issues related to anger, for example, which are a separate phenomenon. There could be underlying substance use issues. There could be a whole host of other risk factors for violence going on.”

“I think we have a long way to go in terms of brain science to really understand [those] distinctions,” adds Ron Honberg, a senior policy advisor at the National Alliance on Mental Illness

But when the news reinforces these easy narratives, as McGinty’s study shows it often does, that can have serious consequences. Other research shows that reading stories about mass shootings by people with mental illnesses makes people feel more negatively toward the mentally ill. This only heightens stigma, which could lead to more people going untreated.

“Do we not risk creating further barriers?” Honberg asks. “People [may] feel like, ‘Oh my gosh, if I get identified as having a psychiatric diagnosis, people are going to draw certain conclusions.’ It’s hard enough to get people to seek help when they need it.”

Shootings seem to inevitably lead to people calling for better mental health screenings for guns, or for better mental health care generally. Which would be great, lord knows we need it. But again, better mental health care is not going to have much of an impact on interpersonal violence.

This is a misframing of the issue. There is a compelling reason to adjust policy to better keep some seriously mentally ill people from accessing guns. It’s not because they might hurt others, but because they might hurt themselves.

Though big, scary mass shootings get the most attention when it comes to gun violence, 60 percent of deaths caused by firearms are suicides. And another new study in this same issue of Health Affairs emphasizes that suicide, not homicide, is the major public health problem for mentally ill people with guns. In it, Swanson and his colleagues looked at 81,704 people getting public health services for schizophrenia, bipolar disorder, or major depressive disorder in two large Florida counties. They tracked these people’s death records, as well as whether they were barred from owning guns.

In that group, the rate of people who died by suicide was four times higher than that of the general population. The violent crime rate was just under two times higher. But consider that this is a group of people receiving government care, who “might have other risk factors for violence, including poverty and social disadvantage, unemployment, residential instability, substance use problems, history of violent victimization, exposure to neighborhood violence, or involvement with the criminal justice system,” the study reads. So you can’t reasonably attribute the higher violent crime rate in this group to mental illness alone.

Maybe also because many people in the group likely lived in poverty, they were less likely to commit suicide by gun than the general population (perhaps they could not afford one). But 72 percent of the people who did kill themselves with a gun were “legally eligible to purchase a gun on the day they used a gun to end their life,” Swanson says. “That suggests a problem with the criteria we have for identifying people at risk.” And the 28 percent who were not allowed to purchase guns managed to find one anyway, so the laws we do have are not perfectly enforced.

“It’s a big public health opportunity to limit access to guns,” Swanson says.  And it could make a big difference for suicide attempt survival rates. Among people who’ve survived a suicide attempt, more than 90 percent do not go on to kill themselves later. But guns are the most common method of suicide, and people who try to kill themselves with a gun usually succeed—85 percent of the time. “They don’t get that second chance,” Swanson says.

Overall, the study concluded, “[the results] would seem to suggest that suicide, not homicide, should be the crux of gun violence prevention efforts focused on people with serious mental illnesses in public systems of care.”

That is not typically the case, though. Both Honberg and Swanson say that in their experience, people talk about increasing gun background checks for people with mental illness in the context of preventing homicide, not suicide. This is a conversation that plays out in the media and among politicians time and time again after a prominent shooting tragedy, perhaps because talking about mental illness is easier than talking about the guns.

“We’re a pretty violent society here in America and the conversation really ought to focus on what can be done to make America a less violent society,” Honberg says. “But because that discussion is so fraught with emotion and divisiveness and political disagreements, it almost seems like the conversation has devolved to a relatively small subset of people who engage in violence, namely people with mental illness. We can at least agree about what to do with guns and mentally ill people rather than what to do about guns generally. But that’s really passing the buck.”