Suicide Check

It is a crisis that few in the emergency room are equipped to handle. Concerned friends have just arrived with a frightened man in his 20s. He is not bleeding. Nothing's broken. Yet he cannot stop crying, and his companions are worried that he might kill himself. Is he just having a bad night, or is he likely to do himself harm? When it comes to determining an individual's desire to commit suicide, physicians rely heavily on experience and intuition. There has never been a laboratory test that doctors could order that would help them measure the risk more precisely.

That predicament seems likely to change in the next few years, as scientists learn more about the biochemistry of behavior. Some of the latest research -- parts of which were presented at last week's meeting of the Society for Neuroscience in Miami -- suggests that measuring the levels of certain chemicals in the brain can identify those people with a biological predisposition to self-destruction. "More than 95% of the people who commit suicide show these changes in the brain ((at autopsy))," says Dr. John Mann of the Columbia University College of Physicians and Surgeons in New York City. "But the biochemical abnormality is there even in those who attempt to kill themselves. And it is most pronounced in those who make the most dangerous attempts."

A lab test for suicide -- the eighth leading cause of death in the U.S. -- sounds incredible. Yet it is only one of the promising developments being pursued in the hot new field of biological psychiatry. What was once the purview of priests and analysts, who try to probe the mind by listening and observing, is now a frontier for neuroscientists, who use blood tests, brain scans and spinal taps. Psychiatrists at some research centers are already using these tools to distinguish among types of depression and schizophrenia, and predict with some degree of certainty the best course of treatment for their patients.

There have been setbacks. Despite compelling evidence that manic depression, a mental illness characterized by extreme mood swings, runs in families, no one has isolated the genes responsible for the disorder. Several candidates have been identified, only to be discarded. But while the geneticists have hit a snag, the brain chemists are moving faster than anyone thought possible, and have produced an impressive array of practical results.

Nowhere is this bonanza more apparent than with the research into the brain chemical called serotonin. One of the many signaling chemicals used by nerve cells to communicate with one another, serotonin is intricately linked to those parts of the brain that affect mood and impulse control. Nerve cells manufacture, release and absorb serotonin in quick bursts that ripple throughout the cerebrum. Although no one understands quite why, low levels of the chemical are associated with clinical depression. As a result, serotonin has become the target for a whole new genre of antidepressant drugs -- the most popular of which is Prozac -- that keep it active in the brain longer than usual.