Sally Adee, reporting for New Scientist, explains:

To develop the test, over several years Niculescu’s team took blood samples from 217 men undergoing various psychiatric treatments. They compared changes in gene expression in 37 of them who developed suicidal feelings with previously published work and with post-mortem samples of 26 men who had killed themselves. They identified 11 gene changes that could be biological markers for spotting people who might be considering suicide, and they monitored these same markers in a test group of 265 men with psychiatric conditions.

The questionnaire asked the subjects about their physical energy as well as their feelings about their accomplishments, but avoided direct questions about suicide. In a trial of 108 people, the scientists’ predictions of suicidal ideation was 92% accurate, and in a second trial of 157 people, they predicted which men would be hospitalized from a suicide attempt that year with 71% accuracy.

The test was especially accurate when predicting suicidal thoughts within the next year in people with bipolar disorder, predicting correctly 98% of the time. It even predicted with 94% accuracy who would make a serious suicide attempt that would require hospitalization.

Other methods to detect psychiatric disorders are often subjective, but this test uses biomarkers, or biological indicators of a disease. In this case, the biomarker is in the patient’s gene expression as measured by the RNA levels in their blood. (Translation of DNA to RNA is the first step when a gene is expressed. Many of our genes are not expressed at any given time.) Still, biomarkers aren’t a panacea because the genetic biomarkers won’t occur in all patients with a psychiatric disorder. Plus, if doctors start to rely on them heavily, they could overlook the correct disease if the patient doesn’t have the biomarkers for it.

There are doubts about its effectiveness on the general population, since only 16 people out of every 100,000 commit suicide. Right now, the test could provide too many false positives and false negatives for use in the general population to be safe, but could be helpful for those already diagnosed with psychological disorders, since doctors could make further decisions on treatment of those patients, including the length of hospital stays and medication.