Researchers have found that an important brain chemical is more active in the brains of people who attempt suicide.
An international research team led by Michigan State University’s Lena Brundin, M.D., Ph.D., found evidence that glutamate — an amino acid that sends signals between nerve cells and has long been suspected as involved in depression — is more active in the brains of people who attempt suicide.
Brundin and her colleagues examined glutamate activity by measuring quinolinic acid, which flips a chemical switch that makes glutamate send more signals to nearby cells, in the spinal fluid of 100 patients in Sweden. About two-thirds of the patients were admitted to a hospital after attempting suicide, while the rest were healthy.
They found that those who had attempted suicide had more than twice as much quinolinic acid in their spinal fluid as the healthy people, which indicated increased glutamate signaling between nerve cells.
Those who reported the strongest desire to kill themselves had the highest levels of the acid, reported Brundin, a professor of translational science and molecular medicine in MSU’s College of Human Medicine.
The results also showed decreased quinolinic acid levels among a number of patients who came back six months later, when their suicidal behavior had ended.
According to the researchers, the findings explain why earlier research pointed to inflammation in the brain as a risk factor for suicide. The body produces quinolinic acid as part of the immune response that creates inflammation.
Brundin noted that anti-glutamate drugs are in development and could soon offer a tool for preventing suicide. She points out that recent clinical studies have shown the anesthetic ketamine, which inhibits glutamate signaling, is extremely effective in fighting depression, though its side effects prevent it from being used widely today.
In the meantime, Brundin said physicians should be aware of inflammation as a likely trigger for suicidal behavior.
“In the future, it’s likely that blood samples from suicidal and depressive patients will be screened for inflammation,” she said. “It is important that primary health care physicians and psychiatrists work closely together on this.”
The study was published in the journal Neuropsychopharmacology.
Source: Michigan State University