New biological evidence reveals link between brain inflammation and major depression

Posted on January 29, 2015

A new study by the Centre for Addiction and Mental Health (CAMH) found that the measure of brain inflammation in people who were experiencing clinical depression was increased by 30 per cent.

"This finding provides the most compelling evidence to date of brain inflammation during a major depressive episode," says 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."

Specifically, Dr. Meyer’s research team was able to measure the activation of immune cells, known as microglia, that play a key role in the brain’s inflammatory response.

To investigate whether brain inflammation was increased in people during clinical depression, Dr. Meyer and his team conducted brain scans on 20 patients with depression but who were otherwise healthy and 20 healthy control participants using a brain imaging technique called positron emission tomography (PET). Results showed a significant elevation of brain inflammation in participants with depression. Rates of inflammation were also highest among those with the most severe depression.

Although the process of inflammation is one way that the brain protects itself - similar to the inflammation of a sprained ankle - too much inflammation may not be helpful and can be damaging. A growing body of evidence suggests the role of inflammation in generating the symptoms of a major depressive episode such as low mood, loss of appetite, and inability to sleep. But what was previously unclear was whether inflammation played a role in clinical depression independent of any other physical illness.

"This discovery has important implications for developing new treatments for a significant group of people who suffer from depression," says Dr. Meyer, who also holds a Canada Research Chair in the neurochemistry of major depression. "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."


Source material from University of Toronto

Mental Health News

  • Human-Centered Approach for Dementia Patients

    newsthumbA group of researchers recently conducted a randomized controlled trial to evaluate the impact of applying a human rights based approach in dementia ...

  • 6 Signs of a Codependent Relationship

    newsthumbCodependency can be recognised when two people with dysfunctional traits become worse together. The biggest issue is the belief by one or both ...

  • ODD and the Rebellious Child

    newsthumbOppositional Defiant Disorder (ODD), while exhibiting symptoms that sound very much like a typical rebellious child's behavior, is a disorder that ...