American researchers have identified a genetic indicator that could be used to predict a person’s risk of attempting suicide.
The indicator can be detected using a simple blood test, meaning therapists and doctors could be made aware of suicidal tendencies before it is too late for them to intervene.
"With a test like ours, we may be able to stem suicide rates by identifying those people and intervening early enough to head off a catastrophe," says lead author Dr Zachary Kaminsky from Johns Hopkins University School of Medicine.
As reported in The American Journal of Psychiatry, the study focused on a mutation of the SKA2 gene, which is involved in keeping levels of the stress hormone cortisol under control.
When Kaminsky and team analysed brain samples from healthy people and people who were mentally ill, they found that SKA2 levels were significantly reduced in samples taken from people who had committed suicide. The team also noticed that in some samples, an epigenetic modification had occurred that disrupted the normal function of SKA2 rather than altering its DNA sequence. This modification is referred to as methylation because it involves the addition of methyl groups to the gene.
Further research showed that the level of SKA2 methylation was also higher in samples from people who had committed suicide. The team then examined the degree of SKA2 methylation in two further independent cohorts and confirmed that higher levels of SKA2 methylation were indeed detected among those who had taken their own lives.
Next, Kaminsky and colleagues designed a model for predicting suicide risk based on blood test results from 325 participants recruited at the John Hopkins Center for Prevention Research. The researchers found that the model could predict who was at the greatest risk of suicide with 90% accuracy. Whether or not someone had already attempted suicide could also be predicted, with an accuracy of 96%.
“We have found a gene that we think could be really important for consistently identifying a range of behaviors from suicidal thoughts to attempts to completions,” Kaminsky says. “We need to study this in a larger sample but we believe that we might be able to monitor the blood to identify those at risk of suicide.”