Abnormality Found in Brains of Suicide Victims
Scientists reported Tuesday that they have detected a new abnormality in the brains of a group of suicide victims, a discovery that may lead to better ways of identifying and treating suicide-prone people.
Researchers from New York University and Israel’s Weizmann Institute of Science compared brain tissues from 12 people who committed suicide and were not on psychiatric drugs with similar tissues from 12 people who died of other causes.
They found that the suicide victims’ brain cells had much larger numbers of a protein structure called a mu opioid receptor. The biggest difference, nine times the normal number, was seen in areas of the brain involved with sensory and motor function.
The people who killed themselves also had 50% fewer of another type of opioid receptor, called delta, in several brain regions, including the area that governs memory.
“We may be able to find a whole new family of drugs that act on these receptors, help treat depression and prevent suicide,” said neurobiologist Anat Biegon of New York University, a co-author of the study.
Biegon emphasized, however, that it is still not known if living people who attempt suicide or non-suicidal depressed people have opioid receptor imbalances similar to those of suicide victims. Another unanswered question is whether the unusual distribution of receptors stems from excessively high or excessively low levels of opioids in the brain.
Past studies have linked suicide only to changes involving the brain chemicals serotonin and norepinephrine. But the new study, presented at the Society for Neuroscience’s annual meeting, is the first to associate changes in the opioid system with suicide.
Opioids, which are naturally occuring chemicals in the body, induce pain-killing and euphoria-producing effects similar to opium-based drugs such as heroin and morphine.
Doctors had observed that severely depressed patients experience a reduced ability to experience pleasure and are more likely to suffer from chronic pain than non-depressed people.
Changes in opioid-binding receptors in the brains of living people now can be mapped by sophisticated imaging techniques such as positron emission tomography, Biegon said.
If the findings in dead people hold up in living patients, it is possible positron emission tomography could be used to detect which depressed people are most likely to kill themselves.
