New stress-causing mechanisms in depression discovered
When people suffer from depression, their brain region, which is responsible for stress control, is enlarged at the same time. This could result in an increased level of the stress hormone cortisol, which leads to permanent tension, which depressives often suffer from. A German research team from the Max Planck Institute comes to this knowledge.
Researchers from the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig and the Leipzig University Hospital recently found in an investigation that the left side of the hypothalamic brain region decreased by an average of five percent in patients suffering from an affective disorder is enlarged. The scientists see this as the reason why people with depression are increasingly exposed to stress. The study results were recently published in the journal "Acta Psychiatrica Scandinavica".
Widespread disease depression
Depression is one of the most common mental illnesses worldwide. The World Health Organization (WHO) states that around 322 million people were affected by the mental disorder in 2015. This corresponds to 4.4 percent of the world population. Despite the frequent occurrence, the exact causes of the depression are still unclear.
The search for the triggers
As the MPI researchers report, past research has increasingly come to the conclusion that the disease is probably caused by a combination of genetic disposition and stress factors from the environment. It is already known that the body's stress system does not work properly in people with a higher genetic predisposition to depression.
How the stress system works in the body
The stress system is called the hypothalamus-pituitary-adrenal cortex (HPA) axis. This is usually activated when we are in a stressful situation, for example in a dangerous situation or a challenge that requires more energy from the body. The HPA axis ensures an increased release of the stress hormone cortisol, which ensures higher performance in the short term. The HPA axis then normally ensures that the distribution is reduced again.
How the stress system reacts in depressed people
"However, this is not the case for people with depression or an increased risk of it," the MPI scientists write in a press release on the study results. The feedback mechanism does not work here. The stress system would remain in the high performance mode even though there was no apparent stress situation.
The hypothalamus is enlarged in depressed people
"We have observed that this brain region is enlarged in both people with depression and with bipolar disorder," reports Stephanie Schindler, the study's first author. Both are forms of an affective disorder. The researchers were able to prove in 84 test subjects that the left hypothalamus is larger on average in people with an affective disorder than in healthy people.
The more severe the disease, the larger the brain region
In addition, the researchers were able to show that the more severe the affective disorders, the larger the brain region, which is about the size of a one-cent piece. In addition, the MPI scientists were able to document that medication with antidepressants had no influence on the size of the hypothalamus.
Uncertainties despite new knowledge
"We do not yet know what role the larger hypothalamus plays in depression or bipolar disorder," said Stefan Geyer, one of the study directors. The scientists believe that the increased activity of the hypothalamus may cause the plastic changes and thus bring about the larger volume. (vb)