Could Blood Test One Day Predict Suicide Risk?
Levels of certain proteins may indicate vulnerability, preliminary research suggests
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, Niculescu said.
It's not clear why the proteins were related to suicide risk. And Luther said the findings do not mean that spikes in the proteins "cause" people to commit suicide. "It's just a correlation," he said, and not a cause-and-effect relationship.
But he and Niculescu said the findings could eventually give some insight into the biology of suicide.
First, however, Niculescu said additional studies need to look at women and people of other ethnicities since the men in this study were all white. (One postmortem blood sample was from a black man.) They also need to focus on patients with other mental illnesses, such as major depression, he added.
Dr. Morton Silverman, senior science advisor to the Suicide Prevention Resource Center in Washington, D.C., agreed that the findings are preliminary and limited to this particular group of men.
Another issue, Silverman said, is the way the study defined "suicidality" in the men with bipolar disorder. They were considered to be "high" in suicidal ideation if they had attempted suicide, or if they'd had "any thoughts" about their own death, or wished they were dead. But those are very different states, Silverman noted; someone with a past suicide attempt is clearly at increased risk, while someone who has thought about death may not be suicidal at all.
Still, he praised the "sophistication and creativity" of the work, in finding blood markers that might be associated with "a range of suicidal thoughts, intent or attempts," at least in this group of men.