How Does Long-Term Depression Affect the Brain?
Researchers have now found that untreated depression causes permanent biological changes in the brain. If depression is not treated in time, it leads to increased inflammation of the brain.
In their investigation, the University of Toronto scientists found that depression that had not been treated for years caused a significant increase in inflammation in the brain. The experts published the results of their study in the English-language journal "The Lancet Psychiatry".
Depression doesn't just have an immediate impact
In today's performance society, more and more people suffer from depression. If these are not treated in time, they can lead to changes in the brain, which can increase the likelihood of inflammation, the authors say. This shows that depression is not just a biological disorder with immediate effects. Depression changes the brain over time in a way that requires other forms of treatment that are not yet available, doctors add.
Study had 80 participants
This was a relatively small study with only 80 participants. 25 subjects had untreated depression for more than ten years. Depression was never diagnosed in 30 participants. All participants were examined using so-called positron emission tomography (PET) scans to locate a specific type of protein that results from the brain's inflammatory response to an injury or disease.
Inflammation can protect the body
The right amount of inflammation throughout the body, including the brain, protects against disease and helps the body heal injuries, the researchers explain. However, too many inflammations lead to chronic diseases, including heart diseases and possibly neurodegenerative diseases such as Alzheimer's and Parkinson's, the experts say.
Where do most inflammations occur?
Assuming that long-term depression leads to more inflammation, the researchers expected in their study that they would find more protein in the brain of those who had longest untreated depression. And it was precisely this assumption that was finally confirmed. Increased inflammation was particularly noticeable in a handful of brain areas, including the prefrontal cortex, the area of the brain that is important for thinking.
More research is needed
If the results can be confirmed by other larger studies, this is an important finding that depression has similarities to degenerative diseases such as Alzheimer's and changes the brain in a way that research has not yet fully understood. Increased inflammation in the brain is a common reaction to degenerative brain diseases, such as Alzheimer's and Parkinson's disease, the scientists explain.
People with depression have 30 percent higher CRP levels
These results build on a study published in 2016. This showed that patients with depression compared to non-ill people have a higher proportion of C-reactive protein (CRP), which is another biological inflammation marker. Overall, people with depression had 30 percent higher CRP levels than healthy people.
Depression is a biological brain disorder
We may need to change our thinking about depression and its effects, the scientists say. The study confirms that depression is really a biological brain disorder that takes an uncontrolled degenerative course that damages brain tissue - possibly in a way that resembles other neurodegenerative diseases. The results underline the need to develop more effective treatment methods, the doctors concluded. (as)