A blood test for suicide?
By the time you count to 40, someone in the world will have committed suicide.
Nearly one million people kill themselves every year, according to the World Health Organization. This means that every 40 seconds, somewhere across the globe, someone is ending his or her own life.
But what if a blood test could predict what this person was going to do?
It's an intriguing idea now gaining traction thanks to a new study published by Molecular Psychiatry. According to lead researcher Dr. Alexander Niculescu with Indiana University, his team has provided the first "proof of principle" that molecular signals, or biomarkers, could potentially identify people at risk of suicide.
"There are people who will not reveal they are having suicidal thoughts when you ask them, who then commit it and there's nothing you can do about it," Niculescu said in a press release. "We need better ways to identify, intervene and prevent these tragic cases."
The study went through several steps before Niculescu and his team identified the four top biomarkers that they believe could help predict suicides:
1) Identifying which biomarkers to look for. The researchers interviewed and collected blood samples from 75 white males with bipolar disorder. They then honed in on nine men who went from having no suicidal thoughts to seriously contemplating suicide, identifying several biomarkers that were linked with that dramatic shift.
2) Honing in on the best biomarkers. Next, working with a coroner's office in Indiana, the researchers scoured for biomarkers in nine "suicide completers" – men between 26 and 68 who died from hanging, gun shot wounds or, in the case of one 65-year-old man, slitting his wrists. This allowed them to narrow down their list of 41 biomarkers to six, with the biggest red flag being the expression of the SAT1 gene – high levels were found in all nine suicide victims.
3) Testing whether the biomarkers could predict hospitalizations for suicide attempts. Finally, researchers looked at 42 white men with bipolar disorder and 46 white men with schizophrenia and followed up on those who were hospitalized. They found high blood levels of four biomarkers, especially SAT1, in patients with "future suicide-related hospitalizations" as well as hospitalizations that occurred before their blood was tested.
"Taken together, our results have implications for the understanding of suicide," the researchers write in their study's conclusion. "Given the fact that approximately one million people die of suicide worldwide each year, and this is a potentially preventable cause of death, the need for, urgency and importance of efforts such as ours cannot be overstated."
But this study is only an initial exploration and has several limitations – the sample size is small, for one, and includes only white males. Niculescu hopes to do more a more extensive population study in the future.
Other scientists also caution the findings need to be replicated before any conclusions can be drawn – and in an interview with The Independent, Professor Matthew Hotopf with King's College London was particularly skeptical.
"It's one thing to find a biomarker which might be associated at a statistical level with suicide/suicidal behaviour. It's quite another to use it to make any kind of prediction which has clinical utility," Hotopf told Independent reporter Heather Saul.
"These findings may attract media attention, but they are very much preliminary and my money would be on failed replication and even if replication was successful, lack of predictive power to be a useful clinical tool."