Researchers say they’ve discovered that a chemical alteration to a single gene could make a person at risk of attempting suicide. If confirmed, these findings, published in the American Journal of Psychiatry this week, could be translated into a simple blood test to predict suicide risk.
“Suicide is a major preventable public health problem, but we have been stymied in our prevention efforts because we have no consistent way to predict those who are at increased risk of killing themselves,” Zachary Kaminsky of Johns Hopkins says in a news release.
This gene of interest, called SKA2, is linked with the brain’s response to stress hormones. Changes to this gene could turn everyday strain into suicidal thoughts. SKA2 is expressed in the prefrontal cortex of the brain, which is involved with inhibiting negative thoughts and controlling impulsive behavior. SKA2 is specifically responsible for chaperoning stress hormone receptors, and if there’s not enough SKA2 -- or if it’s altered in some way -- someone under stress won’t be able to shut down the effect of the stress hormone.
First, Kaminsky and colleagues looked at postmortem brain samples from healthy people and people who were mentally ill, some of whom had committed suicide. In samples from people who died by suicide, levels of SKA2 were significantly reduced.
Within this mutation (which is pretty common), they looked for epigenetic modifications -- chemical triggers that modify DNA by turning genes on or off. These could alter the way SKA2 functions without changing the gene’s underlying DNA sequence. One type of modification is the addition of methyl groups (one carbon bonded to three hydrogen atoms) to a gene. The researchers found higher levels of methylation in those who committed suicide; it seems they were unable to “switch off” the effect of the stress hormone.
The team then tested hundreds of blood samples using a model they designed to predict the participants who were experiencing suicidal thoughts or had attempted suicide. They predicted severe risk of suicide with 90 percent accuracy.
A simple blood test based on these findings could help determine the need for hospitalization or how close an at-risk person should be monitored. However, because there are scales of severity and varying spectrums of contemplating, planning, and attempting suicide, Kaminsky says the biomarker may not be a determining test for all cases.
Furthermore, being vulnerable to stress and anxiety doesn’t make a person destined to experience suicidal thoughts -- it could just as well show resilience. It’s like a person trying to cross the street, Kaminsky explains to the Washington Post. It doesn’t make you destined to be hit, but might encourage you to be a more aware pedestrian.