Genes that increase risk of 'suicidal thoughts'

According to a recent study published in the journal JAMA Psychiatry, suicidal tendencies may run in families. Four genes that increase the likelihood of suicidal thoughts and deeds were found in the study of US military personnel. 

Scientists from Duke University Medical Center say their findings advance our understanding of how inherited risk factors contribute to the emergence of suicidal thoughts and risky behaviour, though more research is required to determine whether identifying these genetic markers might lead to targeted treatments.

“It’s important to note that these genes do not predestine anyone to problems, but it’s also important to understand that there could be heightened risks, particularly when combined with life events,” said Nathan Kimbrel, PhD, associate professor in the Department of Psychiatry & Behavioral Sciences at Duke, in a media release.

More than 630,000 US military veterans' data was used in a comprehensive genome-wide analysis carried out by Prof. Kimbrel and his colleagues. 

Over 70% of this group had European ancestry, 19.1% had African ancestry, 8.1% had Hispanic heritage, and 1.3% had Asian ancestry. The majority of participants were male.

Medical records for the group of veterans showed 121,211 instances of suicide ideas or deeds. Those participants who had no known history of self-harming behaviour were categorised as controls.

The research team discovered many genes through a genome-wide examination of blood samples present in patients with confirmed cases of suicidal thoughts or behaviours, independent of their ancestry. The strongest connections were found between four genes that have also been linked to psychiatric disorders.

One of these, the estrogen receptor ESR1, has previously been discovered to be the hereditary cause of PTSD and depression, both of which increase the likelihood of suicide conduct in veterans.

The loss of ESR1 has been discovered to have negative effects on the brain tissue in men, and estrogen is also thought to be a factor in the sex disparities in depression rates.

The second gene discovered was DRD2, a dopamine receptor that has been linked to risky behaviour, schizophrenia, mood disorders, ADHD, and problem drinking in the past.

The third, known as DCC, has been linked to numerous psychiatric disorders and is expressed in brain tissue. Researchers have discovered increased amounts in the brains of suicide victims.

TRAF3, the fourth gene linked to suicide, has been linked to antisocial behaviour, substance misuse, and ADHD.

Are there treatment options?

According to Prof. Kimbrel, lithium, a "gold standard" medication for bipolar disorder that has been demonstrated to lower the risk of suicide, regulates the expression of TRAF3 and a number of other inflammatory genes. The research team also discovered nine other ancestry-specific risk genes in addition to those four.