Yet Friday morning’s headlines were frantic about the possibility that Lubitz could have been depressed. The Daily Mail, ever over-the-top, went with: “Mass-killer co-pilot who deliberately crashed Germanwings plane had to STOP training because he was suffering depression and 'burn-out.'” CNN’s homepage blared “Unfit to Work” in all-caps.

“It’s kind of natural to say ‘This just has to be deeply crazy,’” says Jeffrey Swanson, a professor of psychiatry and behavioral sciences at Duke University who studies violence and mental illness. But people who commit mass murder “are really atypical of people with mental illness,” he says. “The vast majority of people with schizophrenia, bipolar disorder, or major depression are not likely to do anything violent and never will.”

By one measure, only 5 percent of violent crime is actually attributable to mental illness. For depression specifically, a study of more than 47,000 people in Sweden found that 3.7 percent of men and 0.5 percent of women diagnosed with depression committed a violent crime, The Guardian reported. In the general population, those numbers were 1.2 percent for men, and 0.2 percent for women. Depression is a risk factor, then, but a very small one.

“There’s this disconnect, but that becomes a prism through which we see these problems,” Swanson says.

People are understandably upset by this portrayal of Lubitz, which makes the leap to equating mental illness and violence, using only the very limited evidence of this one situation. Masuma Rahim, in an op-ed for The Guardian, worries that news reports blaming depression could “further [demonize] those with mental illness.”

To conclude that his role in the crash was the automatic consequence of any history of mental illness would be irresponsible and damaging. There has been no suggestion that males should be prohibited from becoming pilots, that Germans are unfit to fly, or that 27-year-olds should not be let loose in the cockpit. Only one factor has been picked over: Lubitz’s mental health.

This is an all-too-familiar progression. Within the past few years alone, the Newtown shooting, the Aurora shooting, and the Navy Yard shooting all come to mind, for how quickly the conversation turned from the killers’ actions to their minds. The impulse is understandable. Mental illness can be treated, and in the face of horror, people want action. What can we do to prevent this from ever happening again?

“A horrifying act like this, on the face of it, is deeply irrational, it’s terrifying and it seems unpredictable,” Swanson says. “It’s everything that we don’t want our everyday life to be. We want everyday life to make sense. We want to be able to predict what’s going to happen when we get on a plane, get in a car, or go to a shopping mall.”

Now, in the wake of the Germanwings crash, people are calling for better mental health screenings for pilots. Better screenings, earlier intervention, improvement of the mental health system all-around—these are noble goals. But unfortunately, the impact they could have on preventing future violence is probably small.