No Easy, Reliable Way To Screen For Suicide

Mar 31, 2015
Originally published on April 1, 2015 6:57 pm

Even a careful psychiatric examination of the co-pilot involved in last week's Germanwings jetliner crash probably would not have revealed whether he intended to kill himself, researchers say.

"As a field, we're not very good at accurately predicting who is at risk for suicidal behavior," says Matthew Nock, a psychology professor at Harvard. He says studies show that mental health professionals "perform no better than chance" when it comes to predicting which patients will attempt suicide.

Nock made the comments after German authorities said that the co-pilot, Andreas Lubitz, had once received treatment for suicidal tendencies. Lubitz is suspected of deliberately crashing the Germanwings plane into the French Alps, killing 150 people onboard.

Most of what scientists know about suicide comes from studies of the general population, not pilots, says Guohua Li, who directs the Center for Injury Epidemiology and Prevention at Columbia University. Only one or two pilots a year kill themselves by crashing an airplane, he says, and they are nearly always general aviation pilots flying alone.

Li was a coauthor of a study in 2005 that looked at several dozen pilot suicides. It found many of them fit a profile: young, male, with a history of mental health problems and relationship problems. That profile appears to fit the Germanwings pilot "very, very well," Li says.

But the profile also fits thousands of pilots who will never have any problems while flying, Li says. "There is no reliable way for any airline to predict which pilots are going to commit suicide by airplane," he says.

Airlines could improve safety by aggressively screening pilots for alcohol and illicit drug use, Li says. The U.S. does this, but most other countries do not, he says.

One reason mental health professionals often get it wrong when it comes to suicide is that they know only what people are willing to tell them, says Nock. "People are often motivated to deny or conceal thoughts about suicide for fear of being intervened upon or locked in a psychiatric hospital against their will," he says.

Other motivations include fear of being stigmatized or losing a job. But even people who are already in a psychiatric hospital rarely reveal their intentions, Nock says. About "78 percent of people who die by suicide in the hospital explicitly denied suicidal thoughts or intentions in their last interview before dying," he says, sometimes because they lack insight into their own state of mind.

So Nock has been experimenting with tests that are harder to fool. One involves simply indicating the color of words as they appear on a computer screen. Participants push one button for red words and another for blue words, while the computer measures their reaction time.

"If you're thinking about suicide, seeing the word suicide or death interferes with your ability to respond and it takes you just a few milliseconds longer to respond," Nock says. That's probably because the person has an involuntary emotional reaction to the word that slows him down, he explains.

Tests like that can greatly improve predictions about what a person is going to do, Nock says. But they are still experimental and still don't reveal precisely when someone will act.

"To date we've followed people over a six-month period," he says. "What we need to get better at is who's at risk of suicidal behavior imminently, in the next hours or days or even week. And that's where we still have a lot of work to be done."

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Transcript

DAVID GREENE, HOST:

Investigators are still trying to understand why a pilot apparently crashed a commercial plane into the French Alps last week. Yesterday, one more possible clue was revealed. German officials say Andreas Lubitz, the co-pilot on the Germanwings plane, was treated for suicidal tendencies. That was before he got his pilot's license and in treatment since they say he showed no signs of those tendencies. But this raises a question; with that earlier diagnosis, could anyone at the airliner or elsewhere have anticipated his actions? NPR's Jon Hamilton reports that the answer is probably not.

JON HAMILTON, BYLINE: Matthew Nock, a psychology professor at Harvard, has spent years searching for a better way to identify people who are likely to attempt suicide.

MATTHEW NOCK: Right now, the reality is as a society, as a field, we're not very good at accurately predicting who's at risk for suicidal behavior.

HAMILTON: Nock says that's true even when highly trained psychiatrists or psychologists are able to directly question a person about their intentions.

NOCK: Sometimes they're right; sometimes they're wrong. But on the whole, we as clinicians, just using our clinical interview skills and clinical judgment, unfortunately perform no better than chance.

HAMILTON: And the odds may be even worse when it comes to pilots who deliberately crash an airplane. Guohau Li directs the Center for Injury Epidemiology and Prevention at Columbia University. He says one challenge is that there's not much information about these pilots because the crashes are so rare.

GUOHAU LI: Fortunately it happens only about twice a year.

HAMILTON: And Li says nearly all of the crashes involve general aviation pilots flying alone. In 2005, Li co-authored a study that looked at several dozen pilot suicides. He says what emerged was a pretty clear profile.

LI: Male, young, mental health problems such as depression, social problems such as marriage breakdown.

HAMILTON: Also financial problems, legal problems and relationship issues. Li says the co-pilot of the Germanwings plane appears that profile pretty well, but Li says so do lots of other pilots who will never have any problems while flying.

LI: There is no reliable way for any airline to predict which pilots are going to commit a suicide by airplane.

HAMILTON: Li says airlines outside the U.S. could do a better job screening for alcohol and illicit drug use, though it's not clear whether either of those was a factor in the Germanwings crash. Matthew Nock, the Harvard professor, says one reason mental health professionals often get it wrong is that they only know what people are willing to tell them.

NOCK: An especially problematic issue in the case of suicidal behavior is that people are often motivated to deny or conceal thoughts about suicide for fear of being intervened upon or locked in a psychiatric hospital against their will.

HAMILTON: Nock says other motivations include fear of being stigmatized or losing a job. But he says even people who are already in a psychiatric hospital rarely reveal their intentions.

NOCK: Seventy-eight percent of people who die by suicide in the hospital explicitly denied suicidal thoughts or intentions in their last assessment before dying.

HAMILTON: Nock says in some cases that's because they lack insight into their own state of mind, so Nock has been experimenting with tests that are harder to fool. One involves simply indicating the color of words as they appear on a computer screen. Participants push one button for red words and another for blue words while the computer measures their reaction time.

NOCK: If you have suicide on the mind, if you're thinking about suicide, seeing the word suicide or death interferes with your ability to respond, and it takes you just a few milliseconds longer to respond.

HAMILTON: Probably because the person has an involuntary emotional reaction to the word that slows them down. Nock says those tests can greatly improve predictions about what a person is going to do, but he says they are still experimental and still don't reveal precisely when someone will act.

NOCK: To date, we've followed people over a six-month period. What we really want to get better at and what we need to get better at is identifying who's at risk of suicidal behavior eminently - in the next hours or days or even week. And that's where we still have a lot of work to be done.

HAMILTON: Before mental health professionals are able to make reliable predictions about pilots or anybody else. Jon Hamilton, NPR News. Transcript provided by NPR, Copyright NPR.