In a recent study, Yale researchers shed new light on the genetic risk factors underlying suicidal behaviors.

Yale researchers have identified several genes associated with quantitative scores for suicidality using a suicide attempt severity scale. Such associations were found near genes involved in anaerobic energy production, circadian clock regulation and catabolism of tyrosine, an amino acid. The study, which used a sample of over 20,000 individuals, was published in the Translational Psychiatry Journal Jan. 17.

“With suicide being one of the top 10 leading causes of death worldwide, you can help save lives if a better way to treat people is found using psychiatric research,” said lead author of the study Daniel Levey, who works in the human genetic division of the Yale School of Medicine’s psychiatry department.

The team was the first to perform a genomewide association study of the severity of suicide attempts to investigate genetic influences.

The suicide attempt severity scale had a range of zero to four: zero was given for no reported attempt or suicidal ideation, one if an attempt at suicide had been carried out, two if treatment had been received for an attempt, three if medical hospitalization had occurred due to an attempt and four if the methods of suicide attempt was classified as violent.

Levey highlighted that a strength of the study was that it was conducted on people of various ancestries. Of the 6,320 individuals who had the necessary data, there were 2,439 European American subjects and 3,881 African-American subjects.

“Investigating genetic differences across ancestries, this was key, as what might drive behavior in people from one ancestry may differ from another,” Levey said, highlighting that “African ancestry is underrepresented in most genetic studies.”

In addition to finding several genes associated with suicidal behavior, the researchers also found significant genetic overlap with major depressive disorder.

According to the study, suicidal behaviors are driven by many complex interacting genetic and environmental influences, so it is unlikely that any single gene is entirely responsible for the behavior. However, information regarding all the genes that play a role in driving the behavior can collectively provide insight into the genetic risk factors.

“It will not be enough to take individual genetics on their own and predict someone who is at risk, but collectively they could give extra information about whether someone’s genetic background might predispose them to a greater risk,” Levey said.

Even in such a moderately sized sample, finding such significant associations is a good indicator for pursuing future research to acquire more information about the genetic risk factors underlying suicidal behaviors. Thus, Levey noted, the next step for research would involve conducting the study on larger sample sizes.

In 2017, there were an estimated 1,300,000 suicide attempts in the United States, according to the American Foundation for Suicide Prevention.

Sophie Oestergaard sophie.oestergaard@yale.edu