Developing New Treatments for Depression

A new study by the Center for Addiction and Mental Health (CAMH) found that the measure of brain inflammation in people who were experiencing clinical depression increased by 30 per cent over those without depression. The finding has important implications for understanding and developing new treatments for depression.

Senior author Dr. Jeffrey Meyer of CAMH’s Campbell Family Mental Health Research Institute said:

“This finding provides the most compelling evidence to date of brain inflammation during a major depressive episode. Previous studies have looked at markers of inflammation in blood, but this is the first definitive evidence found in the brain.”

Specifically, the 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. 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. It was previously unclear whether inflammation played a role in clinical depression independent of any other physical illness. Current treatments do not target inflammation, and treating depression with anti-inflammatories is one avenue for future research. Treating the inflammation concurrently with alternative therapies for depression offers a possible new approach.

The drive to uncover new ways to target and treat depression is encouraged by the reality that more than half of people with major depression do not respond to antidepressant treatments and 20 to 30 percent do not respond to the first antidepressant treatment. In addition, four per cent of the general population is the midst of a clinical episode. Antidepressants have risks and it is healthier to use alternative therapies that are evidence based, when those methods are available.

Depression is a complex illness that takes more than one change to tip someone into an episode; inflammation in the brain is one of those changes. According to study researchers, this is an important step forward, but current treatments for depression do not target inflammation at this time.