For decades, researchers have looked to human genetics for linkages to mental illness, such as depression, bipolar disorder, and schizophrenia. Patterns of inheritance are murky, but it is clear that “stuff runs in families,” says Dr. Douglas Gray, a psychiatrist and researcher at the University of Utah School of Medicine.
His 2018 study – published in the journal of Molecular Psychiatry – went a step further. It examined four specific gene variants that appear to raise the risk of suicide.
Four percent “of genes in the genome have current evidence associated with suicide risk,” according to the study, which identified the variants as APH1B, AGBL2, SP110 and SUCLA2. Their presence is “noticeably associated with suicide risk.”
“We need to tell people who’ve had a suicide that their family’s at risk,” said Gray, who studies suicide to better understand risk factors and develop prevention programs. This genetic component may account for as much as “45 to 50% of the risk,” he said.
Genetic screenings or simply reviewing family histories could be one method of increasing both awareness and prevention, Gray said.
The study was rooted in the work of another researcher at the University of Utah in 1980: Paul H. Wender. His team of American and Danish researchers in Denmark compared adopted children and their adoptive parents to biological parents and their children.
“They looked at a group of children who were adopted at birth and then grew up and completed suicide,” Gray said. “It turned out that almost all of the risk of suicide was from the biological relatives and not the relatives that raised the child. So your suicide risk doesn’t come from the parents that adopt you, it comes from the parents you never met.”
To put Wender’s revolutionary findings to the test, Gray and a team of geneticists began a project that used statistical resources from the Utah Population Database to study 43 extended families that, through several generations, had exhibited high suicide risk. After controlling for environmental factors, gene variants determined to be prevalent in these families were then tested for their frequency through a generalized sample of 1,300 suicides in Utah.
“We’re able to gather DNA of suicide completers for the past 20 years and actually look for genes that might increase the risk for suicide,” Gray said.
The team also conducted what he described as “psychological autopsies,” interviewing parents of the person who took their life, as well as their siblings, friends and, occasionally, athletic coaches and other outside figures.
What Gray uncovered in part mirrors the story of Jenny Gibson, a mother of two sons in Arizona, whose sister took her own life on Jan. 1, 2008. Four years later, her father died by suicide.
“I was afraid,” Gibson recalled. “What if this is … hereditary?
“My dad was very resilient. He didn’t have a mental illness, he was handling the loss of his daughter like any other parent would – it comes with depression and heartbreak – and I didn’t see anything different.”
Experts say trauma associated with loss of a loved one can heighten levels of suicide risk. Gibson, her father and her sister had never been genetically screened. But Gibson says she is interested in examining those factors, along with environmental considerations, as a way to safeguard herself.
Gray noted, however, that there’s no gene “that dooms you to suicide.”
In a related 2013 study focused on the hereditary nature of mental illness, specifically bipolar disorder, major depression and schizophrenia, researchers found correlation, but they cautioned against overemphasizing genes as a predictor of mental health.
“Although statistically significant, each of these genetic associations individually can account for only a small amount of risk for mental illness,” said the study’s co-author, Dr. Jordan Smoller of Massachusetts General Hospital.
Gray compared the situation to flying.
“When you look at when, sadly, an airplane crashes, there’s usually five or six different things that went wrong all in combination,” he said.
“We’ll have a 17-year-old boy that dies of suicide and yeah, there was a romantic breakup, but if a romantic breakup was the cause of suicide, then none of us would be alive, right?”
Natalia Chimbo-Andrade, director of community education and outreach for the behavioral health agency Community Bridges Inc., works with young people and families in crisis. As a suicide attempt survivor and a mother, she said she sees Gray’s work as an opportunity for a broader conversation: understanding the warning signs of suicide.
“It’s important that as we are having these open and honest conversations with members of our family about genetics and health risks, we also talk about the other contributing factors and, most importantly, we talk about the warning signs – the warning signs that we might see in other people, but also the warning signs that we see within ourselves,” Chimbo-Andrade said. “It is important that we listen to our body physically, but also listen to our body mentally. So when we know about the contributing factors and we know about the warning signs and how to listen to our body mentally and physically, then we can go to the people that can help guide us to the proper resources and support.”
Gray said the proper education and awareness to which Chimbo-Andrade is referring is vital to preventing suicide in families.
“Diabetes runs in families, asthma runs in families … anxiety runs in families, depression runs in families,” he said. “Know your family history. If you have a family history of colon cancer, please get your colonoscopy and get it regularly. If you have a strong family history of significant mood disorders and you’re starting to get depressed, the earlier you get help, the better.
“Let’s try to prevent problems before they get worse.”
This story was produced in partnership with the Arizona Community Foundation.
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