WASHINGTON, July 30 (Xinhua) -- A simple blood test to detect a chemical alteration in a single human gene linked to negative thoughts and impulses may reliably predict a person's risk of attempting suicide, U.S. researchers said Wednesday.
The discovery, described online in the American Journal of Psychiatry, suggested that changes in a gene called SKA2 plays a significant role in turning what might otherwise be an unremarkable reaction to the strain of everyday life into suicidal thoughts and behaviors.
"Suicide is a major preventable public health problem, but we have been stymied in our prevention efforts because we have no consistent way to predict those who are at increased risk of killing themselves," study leader Zachary Kaminsky, assistant professor at the Johns Hopkins University School of Medicine, said in a statement.
"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," Kaminsky said.
In a series of experiments involving brain samples from mentally ill and healthy people, Kaminsky and his colleagues found those who had killed themselves had significantly reduced levels of SKA2.
Further study found in some subjects a modification that altered the way the SKA2 gene functioned without changing the gene 's DNA sequence.
The modification added chemicals called methyl groups to the gene and higher levels of methylation were then found in the same study subjects who had killed themselves.
In the following experiments, the researchers tested blood samples of 325 participants and found similar methylation increases at SKA2 in individuals with suicidal thoughts or attempts.
Based on the findings, they designed a model analysis that predicted which of the participants were experiencing suicidal thoughts or had attempted suicide with 80 percent certainty.
The SKA2 gene is found in the prefrontal cortex of the brain, which is involved in inhibiting negative thoughts and controlling impulsive behavior.
If there isn't enough SKA2, or it is altered in some way, human brain cannot suppress the release of a hormone called cortisol. Previous research has shown that such cortisol release is abnormal in people who attempt or die by suicide.
If confirmed in larger studies, a blood test based on these findings could help doctors make decisions to prevent a tragedy, like the need for hospitalization, closeness of monitoring, or restricting patients' access to certain medications that have been linked with suicidal thoughts.
"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 said. "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."