Chronic stress can lead to depressive symptoms, according to a study led by a professor at Université Laval’s Faculty of Medicine.
Repeated bullying can trigger a barrier between the brain and blood, which can lead to depression, says Caroline Ménard, first author of the study that was published in the latest issue of the journal Nature Neuroscience .
Researchers supervised by Professor Scott Russo of the Icahn School of Medicine at Mount Sinai, New York, were interested in the blood-brain barrier.
They repeatedly placed mice in a cage where, on the other side of a separator, there was a large, aggressive mouse.
breaking down the of the barrier
The team found barrier opening in depressed mice, but not in resilient mice.
“It has been discovered that inflammation in the body is able, when it is chronic, so repeatedly, to open a barrier that [normally] allows the brain to be protected from the harmful circulates in the blood, “says Caroline Ménard.
Observed in humans
The researchers were also able to observe the opening of the blood brain barrier in humans.
“We had the opportunity to work with two brain banks, one in Texas and the Douglas Mental Health University Institute,” says Caroline Ménard.
Some of the people whose brains were removed experienced episodes of depression during their lifetime, while others died without suffering from this disease.
The discovery of the Université Laval study could lead to the development of new treatments or the diagnosis of depression using a medical imaging examination.
“We could have a biological measure, something that is missing in the medical arsenal,” says Caroline Ménard, adding that the diagnosis of depression is currently based on a questionnaire.