Researchers from McGill University and the Douglas Institute have discovered that two different types of brain cells have different functions in patients with depression.
The survey results are natural geneticsprovides important clues that could lead to new treatments designed to target these specific cells. You will also gain a clearer understanding of depression, which affects more than 264 million people worldwide and is a leading cause of disability.
“This is the first time that by mapping the mechanisms that regulate gene activity and the DNA code, we have been able to identify which specific brain cell types are affected by depression,” said lead author Dr. Gustavo Turecki, professor at McGill University, clinical scientist at the Douglas Institute, and Canada Research Chair in Major Depressive Disorder and Suicide. “This allows us to get a clearer picture of where the disruption is occurring and which cells are involved.”
Rare brain tissue enables breakthroughs
To make this discovery, the research team relied on postmortem brain samples from the Douglas Bell Canadian Brain Bank. This collection is one of the few in the world to contain brain tissue donated by individuals with mental illness, making it a valuable resource for studying mental health at a biological level.
Scientists used advanced single-cell genomic technology to examine RNA and DNA from thousands of individual brain cells. This approach allowed them to pinpoint which cells behave differently in depressed patients and identify genetic patterns that may explain those differences. The study included a sample of 59 people diagnosed with depression and 41 people without depression.
Key brain cells show changes in activity
This analysis revealed changes in gene activity in two important types of brain cells. One is a group of excitatory neurons that play a role in regulating mood and responding to stress. The other was a subtype of microglia, immune cells in the brain that help control inflammation.
In both cell types, many genes show different levels of activity in depressed patients, suggesting that these systems may not be functioning properly. These confusions may help explain how depression develops at a biological level.
Rethinking depression as a brain disorder
By identifying the specific cells involved, this study strengthens the argument that depression has a clear biological basis. It also questions outdated views that treat the condition as purely emotional or psychological.
“This study confirms what neuroscience has been telling us for years,” Turecki said. “Depression is not just emotional; it reflects real, measurable changes in the brain.”
Future developments in depression research
The researchers now plan to investigate how these cell differences affect overall brain function. They also hope to determine whether treatments targeting these cells could lead to more effective treatments in the future.
About research
A paper by Anjali Chawla, Gustavo Turecki et al. entitled “Mononuclear chromatin accessibility profiling identifies cell types and functional variants that contribute to major depression” natural genetics.
Funding for this study was provided by the Canadian Institutes of Health Research, the Brain Canada Foundation, the Fondation de Santé du Québec, and McGill University’s Healthy Brains, Healthy Lives Initiative.
