Suicide is the tenth leading cause of death in the U.S., with one suicide occurring every 13 minutes, on average. Predicting who is at risk for suicide is difficult, as behavioral clues are pretty much all doctors and loved ones have to go on. Now, however, researchers say that there might be a physiological warning sign, and that it could be detected with something as simple as a blood test.

Scientists from Johns Hopkins University performed brain analyses on 150 people who had recently died, including some from suicide, the Washington Post reports. They were specifically looking at a group of chemicals called methyls, which affect the a gene called SKA2, which helps control how the brain deals with stress.

"If the gene’s function is impaired by a chemical change, someone who is stressed won’t be able to shut down the effect of the stress hormone, which would be like having a faulty brake pad in a car for the fear center of the brain, worsening the impact of even everyday stresses," the Washington Post explains. People who committed suicide, they found, did indeed have significantly higher levels of methyls, meaning their SKA2 functioning was likely impaired. When the researchers analyzed chemicals in the blood of 325 volunteers they were able to pinpoint with about 85 percent certainty which volunteers were experiencing suicidal thoughts.

As the team told the Post, the mere presence of those biomarkers does not mean that a person will definitely try to kill themselves. It just means they are exceptionally vulnerable to the effects of stress. Nevertheless, it could be a useful tool for applying at prevention centers, for example, to identify those persons whose biology might encourage negative thoughts to manifest in real-world actions.