Stress disturbs the metabolism of sugar and triggers depression

The connection between stress and depression

Ongoing stress is considered a risk factor for the development of mental illnesses such as depression. A German research team recently identified why this relationship exists. Obviously, permanent stress has a negative effect on the sugar metabolism in the brain, causing mental illnesses.

Researchers from the Department of Psychiatry and Psychotherapy of the Mainz University Medical Center and the German Resilience Center Mainz (DRZ) have identified the connection between chronic stress and certain mental illnesses. In the animal model, the study team was able to show how stress alters the metabolism of sugar in the brain and thus triggers the diseases. The findings were recently published in the prestigious science journal "Proceedings of the National Academy of Sciences" (PNAS).

Our brain needs enormous amounts of energy. The brain can be sensitive to a disturbance in the energy balance. Researchers showed in mice that stress alters the sugar metabolism in the brain. As a result, mental disorders can arise. (Image: denisismagilov / fotolia.com)

Stress, sugar metabolism and mental problems go hand in hand

Chronic stress has a negative impact on the metabolism. Especially the sugar metabolism is influenced by stress. The researchers were able to demonstrate for the first time that stress, sugar metabolism and mental symptoms are directly related. For example, the mice studied in combination with stress showed a disruption of glucose metabolism that affected both the blood and the brain.

Why is the sugar metabolism important to the brain??

"The human brain needs a lot of energy even under rest conditions," writes the Mainz science team in a press release on the study results. Ten times that of other organs, the brain needs energy. Thus, this organ is highly dependent on a good energy intake. The brain is often very sensitive to changes in the glucose metabolism.

Stressed mice

For their investigations, the researchers relied on Professor Dr. Marianne Müller a group of mice for a long time under stress. Over time, the scientists were able to document how the animals developed a marked disruption of glucose regulation in the brain. This disturbance lasted even for a longer period of time after the stress phase had already ended. According to the study, it was also noticeable that the brain areas responsible for learning and memory functions were particularly affected

Not all responded equally strongly

In the course of the evaluation, the researchers found that not all animals reacted equally strongly to the persistent stress. There was a particularly sensitive group that reacted with a strong increase in glucose concentration in the brain. Out of this sugar metabolism disorder, the animals developed a memory impairment disorder. In contrast, there was a subgroup of mice that showed very little change due to stress. This group provided similar test results to unstressed animals from the control group.

First treatment attempts

In further tests, the team tried to treat the metabolic disorder with the diabetes drug empagliflozin in order to normalize the metabolism. This led to improved memory in the sensitive group of mice. However, the use of empagliflozin was associated with impaired memory in animals less responsive to stress.

Of humans and mice

"Since people also respond to adverse life situations to varying degrees vulnerable or emotionally resistant, findings on a causal relationship of these factors of high medical relevance," emphasizes Professor. Marianne Müller. From these findings, a personalized treatment against the long-term consequences of stress can arise.

Stress and mental illness are constantly increasing

The results of the study could explain why stress and mental illness are becoming more prevalent in the population. However, it still had to be found out whether the findings could also be transferred to humans, sums up the professor. (Vb)