What Blood Shows Scientists About Suicide Risk

Suicide was responsible for more deaths than motor vehicle crashes were in 2009, but it’s not always easy for doctors to tell when someone is at risk. A new study from the Indiana University School of Medicine and the Indianapolis VA Medical Center has identified a series of biomarkers that could help identify those at risk for suicide with something as simple as a blood test.

Researchers have been looking to biomarkers–traceable biological characteristics, like a certain molecule or gene in the body–that could indicate that a person is at a greater risk for suicide. As of right now, a few different potential biomarkers for suicidal thoughts and behavior have been studied, but none are being used in psychiatric practice yet.

To discover potential changes in gene expression associated with suicidal thoughts, researchers looked at a group of 75 men they were already following as part of a longitudinal study on bipolar disorder. Over the course of multiple lab visits, nine of the men went from having no sign of suicidal thoughts at all to having significant suicidal thoughts. By looking at what changed in their blood and comparing it to the blood of demographically similar men who died from suicide, the researchers were able to pinpoint six likely biomarkers.

"If you ask someone who is intent on committing suicide, they might not tell you [of their intentions]," explains co-author Alexander Niculescu, an associate professor of psychiatry and medical neuroscience at the Indiana University School of Medicine. Niculescu and his colleagues narrowed the list of potential biomarkers with something called Convergent Functional Genomics.

"It’s kind of like Google page rank–the more links to a page, the higher it gets prioritized in your search list," Niculescu says. "Same thing with this approach." For the candidate genes in this study, more independent lines of evidence meant a higher likelihood that the gene would be a biomarker for suicide. They cross-matched the biomarkers they found with previous studies to see if other scientists had found additional links to that gene expression and suicide.