Depression can cause neurons atrophy

Depression inflames the brain

Progressive disease: As depression progresses, the brain changes more and more. A study shows: the longer the condition remains untreated, the more the thinking organ becomes inflamed. A similar phenomenon is known from neurodegenerative diseases such as Alzheimer's. Depression is not one of them. Nevertheless, there seem to be different stages of the disease - which may also have to be treated differently, the researchers write.

Depression is more than just a psychological upset. It has been known since the 1960s that those affected have lost their brain metabolism. There is a lack of neurotransmitters such as the messenger substance serotonin in their brain. But that's not all: In the meantime, researchers have also proven that depression can lead to inflammatory reactions in the thinking organ - reactions that typically occur after brain injuries or in diseases such as Alzheimer's.

On the trail of inflammation

Elaine Setiawan from the Center for Addiction and Mental Health in Toronto and her colleagues have now taken a closer look at this symptom. For their study, they examined a total of 30 healthy people and 50 patients with depression, half of whom had been suffering from the disease for more than ten years and the other half for less than ten years.

With the help of positron emission tomography (PET), the scientists took a look into the brains of the test subjects. Specifically, they were looking for signs of inflammatory immune reactions that can be made visible with the imaging method. Would the concentration of these biomarkers differ depending on the state of health?

Time without treatment is crucial

It turned out that the brains of the depressed subjects were actually more inflamed than that of the healthy ones. In addition, the levels of inflammation seemed to increase with the duration of the disease. The decisive factor was how long the depression had remained untreated, as the team reports.

Those who had not taken medication for severe depression for ten years or more had inflammation levels in the prefrontal cortex, cingulate gyrus and insula 29 to 33 percent higher than in patients who had not taken antidepressants for less than ten years .

A new phase of the disease

For the researchers, this is a sign that there are different stages of the disease. An untreated depression that has lasted longer than a decade is apparently entering a new phase. "Increased inflammation in the brain is a typical response as neurodegenerative diseases such as Alzheimer's and Parkinson's disease progress," says senior author Jeff Meyer of the University of Toronto.

Depression is not a neurodegenerative disease. The changes in the degree of inflammation show, however, that the disease is by no means static. The researchers suspect that depression may have to be treated differently at an advanced stage - for example with drugs that specifically target inflammation in the brain. In the future, the team intends to research in more detail which additional treatment options affected patients could benefit from. (Lancet Psychiatry, 2018; doi: 10.1016 / S2215-0366 (18) 30048-8)

(Center for Addiction and Mental Health, 02/27/2018 - DAL)

February 27, 2018