Every 11 minutes, an American dies by suicide. That’s 132 people a day, or more than 48,000 annually. For those left behind, the haunting question is “Why?”
One emerging factor is family history. In a new analysis of the genetics of suicidal acts, researchers at U of U Health’s Huntsman Mental Health Institute detected more than 20 genes that could have a role in these deaths. The study, among the first comprehensive genome-wide analyses of suicide death ever completed, also found significant genetic cross-connections to psychiatric diseases and behaviors sometimes associated with suicide, such as bipolar disorder, schizophrenia, and autism spectrum disorder.
The study establishes that suicide death is partially heritable and that it tracks in families independent of the effects of a shared environment. Identifying these genetic risk factors, they say, could lead to better ways to predict who might be at risk of suicide and inform new strategies for preventing the worst from happening.
“What is important about this study is that, using the whole genome, we have created a genetic risk score for suicide,” says Anna Docherty, quantitative geneticist and lead author of the study. “It can also help us study how genetics and environment interact to increase suicide risk. We are far from using any genetic risk score in the clinic, but this is the first step to quantifying biological risk for suicide in an individual.”
Although stress, loneliness, financial strains, childhood trauma, and other environmental issues can contribute to death by suicide, scientists have long thought that other factors are involved. “When I tell people that suicide risk is estimated to be 45 to 55 percent genetic, they look very surprised,” says Douglas Gray, professor of child psychiatry and co-author of the study.
To get a comprehensive picture of the genes potentially involved in suicide, Docherty and colleagues used computer technology to analyze millions of DNA variants in 3,413 samples. This is the largest suicide death sample in the world, a major improvement on previous genetic studies. However, the researchers stress that genetics is just one of many factors that can contribute to death by suicide.