New Study Finds Link Between Brain Inflammation and Depression

New Study Finds Link Between Brain Inflammation and Depression

A new study has found that a marker of brain inflammation is increased by 30 percent in people struggling with clinical depression, a finding that may inform the development of new treatments for the condition. Around 10 percent of people in Britain will experience depression in any given year, making it one of the most common mental health conditions in the country, alongside anxiety. The new study adds to existing evidence on the role of inflammation in depression, providing the first indication of inflammation in the brain during depression rather than in the blood, and takes researchers one step closer to pinning down the biological mechanisms which underpin it.

The Study – Do Neurological Scans Reveal Inflammation in Depressed Patients?

The basic aim of the study was to conduct positron emission tomography (PET) scans of both depressed patients and mentally healthy controls, looking for evidence of the activation of immune cells called microglia, which are crucial to the inflammatory response in the brain. The study was conducted on 20 depressed patients and an equal number of healthy controls.

The results showed that, for those who were experiencing clinical depression, levels of these inflammatory response markers were increased by 30 percent. Moreover, the levels of the markers were higher in those experiencing more severe depression, strongly suggesting a link between inflammation and depression.

Senior author Dr. Jeffrey Meyer commented on the findings, “This finding provides the most compelling evidence to date of brain inflammation during a major depressive episode … 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.”

Understanding the Link Between Inflammation and Depression

Like the inflammation that occurs after you sprain an ankle, inflammation in the brain is a protective measure, but too much of it can have negative consequences. In particular, evidence increasingly suggests that symptoms commonly associated with depression, such as insomnia, loss of appetite and low mood are actually consequences of the inflammation.

This is expected to be related to cytokines, which are produced in greater numbers in response to inflammation, and disrupt the normal levels and the release of crucial brain chemicals, including dopamine, serotonin and glutamate. These chemicals are crucial to appetite, sleep, mood, learning and memory, strongly suggesting that inflammation and cytokines have a crucial role in the development of depression symptoms. Additionally, studies show that non-depressed individuals given immune system boosting medicines often develop symptoms of depression.

Dr. Meyer points out that his team’s finding could help lead to a new treatment for depression, since current medicines don’t target inflammation, “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.”

This is particularly important, because many people don’t respond to currently-available depression medicines. However, only around 20 to 30 percent of people with depression have increased inflammation, so the new approach wouldn’t work for everybody either. For those with treatment-resistant depression, though, 45 percent have inflammation, so new inflammation-based treatments could be particularly useful for those who are currently the hardest to treat.


Medication-based treatments for depression may be set to change in the near future, but the psychological support offered by counselling and psychotherapy will continue to be a mainstay of treatment. While medications may be effective at reducing symptoms in some cases, overcoming the psychological habits – for example, ruminating on negative thoughts – associated with depression will continue to be a crucial part of getting better. Inflammation-based medicines may be incorporated into depression treatment in future, but a multi-faceted approach – incorporating both medicine and counselling – will continue to be the best strategy for tackling the condition. For more information on depression counselling London please follow the link.