Researchers at McGill University in Montreal have identified a new molecule present only in humans and primates, low quantities of which could indicate depression. Further research could lead to new treatment options.
The molecule, called miR1202, regulates the reception of an excitatory neurotransmitter called glutamate, says Dr. Gustavo Turecki, a psychiatrist at the Douglas and professor in the Faculty of Medicine, Department of Psychiatry at McGill.
The "mi" in the name researchers gave to the molecule is presumed to identify it as "microRNA," a non-coding regulator of genetic proteins.
Researchers observed miR1202 levels in participants before and after drug-based depression treatment and found their levels of the molecule augmented as the effects of depression subsided.
"In our clinical trials with living depressed individuals treated with citalopram, a commonly prescribed antidepressant, we found lower levels in depressed individuals compared to the non-depressed individuals before treatment," says Turecki. "Clearly, microRNA miR-1202 increased as the treatment worked and individuals no longer felt depressed."
Antidepressants are among the most prescribed drugs in North America and parts of Europe, although response is variable, according to Turecki.
"We found that miR-1202 is different in individuals with depression and particularly, among those patients who eventually will respond to antidepressant treatment."
The research was published in the journal Nature Medicine.
Turecki hopes his discovery will lead to alternatives for patients who respond poorly to current treatment options and offer new hope for all patients with depression.
Although the way it works sounds similar to the mechanisms of melotonin, the naturally occurring sleep hormone available in
most countries in synthetic form as a sleep aid, Turecki says there is no relation between the two.