Among friends and family of those who die by suicide, a common refrain is: I didn't know.
While some people who die by suicide have prior attempts, about half of people who die by suicide have no documented suicidal thoughts or behaviors, nor do they have known psychiatric conditions associated with suicide risk, like depression. They have no previous clear indicators that they might be at risk at all.
A new genetic study at University of Utah found that people in this group of unexpected suicides aren't just flying under the clinical radar via lower access to psychiatric services—their underlying risk factors may be fundamentally different.
The research found that people who die by suicide without prior non-fatal suicidal thoughts or behaviors have fewer psychiatric diagnoses and also fewer underlying genetic risk factors for psychiatric conditions compared to people who had shown these warning signs before dying by suicide.
"There are a lot of people out there who may be at risk of suicide where it's not just that you've missed that they're depressed, it's likely that they're in fact actually not depressed," says Hilary Coon, PhD, professor of psychiatry in the Spencer Fox Eccles School of Medicine at the University of Utah and first author on the study.
"That is important in widening our view of who may be at risk. We need to start to think about aspects leading to risk in different ways."
The results, published in JAMA Network Open , upend conventional beliefs about suicide risk and suggest new approaches to help save lives.
Uncovering hidden risk
Other research had shown that people who die by suicide without prior known suicidality are less likely to have psychiatric diagnoses, such as depression, compared to people with documented suicidal thoughts or behaviors. But nobody knew the root cause of this difference. Maybe, researchers thought, people without known suicidality are still just as depressed or anxious—they're just undiagnosed.
But Coon's team was surprised to find that this isn't the case. Instead, they found that this group has different genetic risk factors from people with known suicidality. By comprehensively analyzing anonymized genetic data from more than 2,700 people who died by suicide, the researchers found that people without prior suicidality tend to have fewer genetic risk factors for several psychiatric conditions, including major depressive disorder, anxiety, Alzheimer's disease, and PTSD.
The genetic data also suggests that this group isn't any more likely than the general population to have milder conditions, like depressed mood and neuroticism.
This means that conventional wisdom on how to reduce suicide may need to be rethought. "A tenet in suicide prevention has been that we just need to screen people better for associated conditions like depression," Coon explains. "And if people had the same sort of underlying vulnerabilities, then additional efforts in screening might be very helpful. But for those who actually have different underlying vulnerabilities, then increasing that screening might not help for them."
Helping those most at risk for suicide
Figuring out how to find and treat these "hidden" at-risk individuals is a major focus of Coon's upcoming research. Previous studies with clinical data have shown potential links between suicide risk and hard-to-treat conditions like chronic pain . Coon is also investigating how other physical disorders, such as inflammation and respiratory conditions, may impact suicide risk. Her work will also focus on traits that may confer resilience to suicide.
Coon emphasizes that, on their own, individual genetic risk factors related to suicide have very small effects on risk, and there's no single gene—or combination of genes—that causes suicide. Environmental and societal contexts are crucial contributors to risk, and understanding the interplay between the environment and underlying biology will be essential to discovering who's at risk.
"We hope our work will begin to define subsets of individuals at risk, and also the contexts in which these risk characteristics may be important," Coon says. "If people have a certain type of clinical diagnosis that makes them particularly vulnerable within particular environmental contexts, they still may not ever say they're suicidal. We hope our work may help reveal traits and contexts associated with high risk so that doctors can deliver care more effectively and specifically. " Better identification of at-risk individuals will help people get the care they need.
