This Blood Test Can Predict Suicide Risk, Scientists Say

Behaviors can’t be reduced to your genes – they’re far too complicated for that. But genes can lay the foundation for making people more or less likely to respond and act in certain ways, and suicide may be the latest example of that.

In a paper published in the American Journal of Psychiatry, researchers led by Zachary Kaminsky, an assistant professor of psychiatry and behavioral sciences at Johns Hopkins University School of Medicine, found reliable differences in the activity of a specific gene among those who had committed suicide and those who had not. They conducted a series of tests to verify their result. First, they studied brain samples of mentally ill people and those not affected by mental illness, and revealed that a gene, SKA2—which is most abundant in the prefrontal regions of the brain that are involved in inhibiting negative thoughts and corralling impulses—was less active among those who ended up committing suicide than among those who had not. If there isn’t enough of SKA2, or if it isn’t working properly, then receptors that pull the stress hormone cortisol into cells to put a brake on the stress response also don’t work. That can lead to unchecked negative thoughts and impulsive behaviors, like a runaway car without brakes.

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The scientists also compared amounts of SKA2 among people with suicidal thoughts or those who had already attempted to kill themselves. Based on levels of the gene’s products in the blood, they could predict with 80% to 90% accuracy whether a particular participant had had suicidal thoughts or had tried to commit suicide.

The differences Kaminsky and his colleagues found isn’t a genetic mutation, but a change in how active the SKA2 gene is. Environmental exposures and life experiences can affect how and when genes are turned on or off. That’s what is happening with SKA2 in those who commit suicide; their gene is inhibited from doing its job of controlling their stress response and modulating it properly.

The work is just the first step in potentially developing a blood test for identifying people at highest risk of harming themselves, says Kaminsky. “We are not going to recommend screening everybody,” he says. “I don’t think that makes sense.” But among those at high risk of suicide, knowing that they also have a possible genetic tendency to react negatively to stress may help to them to get consistent support and more aggressive mental health services to help them cope with their stress and avoid more tragic outcomes.