even in the absence of a psychiatric disorder.
This finding suggests the genetic underpinnings of suicide attempts are partially shared and partially distinct from those of related psychiatric disorders, the investigators note.
“This study brings us a step closer to understanding the neurobiology of suicidality, with the ultimate goal of developing new treatments and prevention strategies,” Niamh Mullins, PhD, department of psychiatry, department of genetics and genomic sciences, Icahn School of Medicine at Mount Sinai in New York, said in an interview.
The study was published online in Biological Psychiatry.
Largest study to date
In the largest genetic association study of suicide attempt published to date, the researchers conducted a genome-wide association study (GWAS) of 29,782 suicide attempt cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC).
Two loci reached genome-wide significance for suicide attempt – the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with suicide attempt after conditioning on psychiatric disorders and was replicated in an independent cohort of over 14,000 veterans in the Million Veteran Program.
“This is the first replicated genetic locus that contributes more to suicide attempt than related psychiatric disorders,” Dr. Mullins said.
“The study found overlap in the genetic basis of suicide attempt and that of related psychiatric disorders, particularly major depression, but also with that of nonpsychiatric risk factors such as smoking, pain, risk-taking behavior, sleep disturbances, and poorer general health,” Dr. Mullins said.
“These genetic relationships between suicide attempt and nonpsychiatric risk factors were not a by-product of comorbid psychiatric illness, suggesting that there is some shared biological basis between suicide attempt and nonpsychiatric risk factors,” she added.
Dr. Mullins cautioned that the findings do not have any immediate impact on patient care.
“The ultimate goal of this research is to gain insight into the underlying biological pathways involved in suicide attempts or suicidal thoughts, providing potential avenues to treatments and prevention strategies,” she said.
“The study findings also point to the importance of studying the potential direct causal paths between these risk factors and suicide attempt in patients with and without psychiatric illness,” Douglas Ruderfer, PhD, of Vanderbilt University Medical Center, Nashville, Tenn., cofounder and cochair of the consortium and senior author of the paper, added in a news release.
A version of this article first appeared on Medscape.com.