Levels of certain blood proteins may rise before a person commits suicide, a small study suggests, and researchers hope the findings will lead to an objective way to measure suicide risk. Any such test is a long way off, experts say. But the new research, published online Aug. 20 in the journal Molecular Psychiatry, is a step in that direction.
Using blood samples from nine men with bipolar disorder, researchers were able to isolate a group of proteins that rose or fell when the men worsened from having no suicidal thoughts to contemplating suicide. What's more, a few of those proteins were particularly high in blood samples from another group of men who had committed suicide.
It all raises the possibility of developing a blood test that could help psychiatrists gauge suicide risk in patients with bipolar disorder or other mental illnesses, such as major depression. "We're not yet ready for a blood test to predict suicide risk," said Luther, who was not involved in the study. But, he added, the results are "interesting," and an objective test for gauging suicide risk is needed.said Dr. Charles Luther, director of inpatient and emergency psychiatry at New York City.
Suicide is, fortunately, relatively rare. Still, over 1 million people worldwide commit suicide each year, and those deaths are preventable so for the new study, the researchers first focused on nine men with bipolar disorder who were part of a larger, long-term research project. During the course of that study, all nine men had gone from having no suicidal tendencies to contemplating or attempting suicide.
Looking back at the men's blood samples, Niculescu's team found 41 proteins whose levels changed when the men became potentially suicidal. Next, the researchers turned to the coroner's office to get blood samples from nine men the same age who had committed suicide. In the end, six proteins stood out as being strongly linked to suicide risk: They had risen in the nine bipolar patients, and were even higher in the men who'd actually gone through with suicide.
The protein with the greatest change was one called SAT1, which is involved in "programmed cell death" -- where damaged body cells essentially commit suicide. Some of the other proteins are involved in inflammation and the body's stress response. Even if a blood test for suicide risk becomes reality, it would only be one part of assessing patients, Niculescu said. "You're not just going to rely on a blood test to recommend that someone be hospitalized," he noted.
Instead, he said, a psychiatrist might use the test along with other information on a patient's risk factors, and questions about his current depression and anxiety symptoms.No single test will ever determine a treatment plan, Luther agreed. "We're dealing with human beings, with complex emotions and experiences," he said. "We need to know more about them than just blood test results."