Researchers have found an intriguing link between brain inflammation and depression that could lead to new treatments.
A recent study found brain inflammation increased an average of 30 percent in people suffering from clinical depression, The Centre for Addiction and Mental Health reported.
"This finding provides the most compelling evidence to date of brain inflammation during a major depressive episode," said senior author Dr. Jeffrey Meyer of CAMH's Campbell Family Mental Health Research Institute. "Previous studies have looked at markers of inflammation in blood, but this is the first definitive evidence found in the brain."
To make their findings the researchers measured the activation of immune cells, called microglia, in the brain's inflammatory response by looking at the brain scans of 20 patients with depression and 20 mentally healthy patients. The scans were taken using a technique called positron emission tomography (PET). The results showed a significant increase in brain inflammation in the patients with depression, and the rates were highest in those with the most severe cases.
Inflammation is a mechanism the brain uses to protect itself from damage, but too much of it can be harmful. Mounting evidence suggests inflammation plays a role in generating symptoms of major depressive episodes, but researchers have been unsure if inflammation was linked to clinical depression independently of other illnesses.
"This discovery has important implications for developing new treatments for a significant group of people who suffer from depression," Meyer said. "It provides a potential new target to either reverse the brain inflammation or shift to a more positive repair role, with the idea that it would alleviate symptoms."
These types of findings are important because over half of people struggling with depression do not respond to antidepressants, the findings suggest these patients could potentially find hope in anti-inflammatory drugs.
"Depression is a complex illness and we know that it takes more than one biological change to tip someone into an episode, but we now believe that inflammation in the brain is one of these changes and that's an important step forward," Meyer concluded.
The findings were published in a recent edition of the journal JAMA Psychiatry.
