Mental stress leaves its mark on the brain

Corona, war, climate worries, are all potential triggers for mental stress. This may lead to irritability, a deteriorating memory or sleep disorders.

The 2024 Congress of the DGIM (German Society for Internal Medicine)

What does the term "stress" actually mean?

In our modern societies, this term is used very imprecisely. Everyone has made or heard the following statements:

Dr Kirsch emphasised in his lecture that such statements about stress do not differentiate between trigger and reaction. From a scientific point of view, the distinction between stressor and stress reaction is crucial: a distinction is made between physiological and psychological stressors. Physiological stressors are characterised by their direct influence on the organism. These include pain, physical effort and the influence of certain substances.  Psychological stressors are usually new, uncontrollable and unpredictable. They also include cognitive effort and social judgement.1

Stress and strain vary from person to person

The stressor itself triggers a stress response as a stimulus. This in turn is a physiological reaction to threatening or aversive situations. The stressor can vary in strength and duration and is objectively detectable. To illustrate this, Dr Kirsch used a further method of visualisation in which the stressor is equated with the strain and the stress reaction with the strain. The strain as a stress reaction is perceived subjectively, but can also be measured objectively using certain parameters. It also varies in duration and intensity and can be accompanied by damage to the affected individual. The respective personal characteristics are the decisive bridge between the latter two.1

Physical stress reactions, in a nutshell:

Dr Kirsch familiarised the audience with the different types of stress reactions:

Mind and spirit demonstrably suffer from constant stress

Chronic stress leads to a disruption of the regulatory circuit in the area of the anterior pituitary-adrenal cortex system.1

Chronic psychological stress makes the body ill

In the long term, chronic stress can lead to all kinds of illnesses via the long-term effects of glucocorticoids. Permanently-elevated blood pressure is known to be associated with cardiovascular disease. It can also lead to damage to muscle tissue (due to permanent tension), stomach ulcers, infertility, sleep disorders and a weakening of the immune system.1

Neuroplastic reactions to chronic stress

Short-term stress can lead to dysfunctional memory formation in the hippocampus. Long-term stress leads to dendritic atrophy in the area of the hippocampus. The consequence of this is a decline in memory. In the medial prefrontal cortex, long-term stress can also induce dendritic atrophy. Here, too, the result is a decline in memory. In the area of the central amygdala, long-term stress leads to increased CRH expression. This is accompanied by increased autonomic excitability and dysphoria. In the basolateral amygdala, the effect of long-term stress is increased dendritic branching. The hypothalamus reacts to long-term stress with reduced GR expression and increased susceptibility to stress. Overall, it can be said that long-term stress leads to remodelling processes in the brain that can significantly impair the brain's ability to regulate acute and newly occurring stress.1

Social-evaluative stress has the most lasting effects on the hypothalamic-pituitary axis

Social-evaluative stress is the most important factor in the development of both somatic and mental illnesses. With regard to the development of sleep disorders, CRH increases play a special role here: they increase the frequency of the sleep EEG, increase light sleep and at the same time reduce slow wave sleep.1

Creating resilience in the "age of stress"

According to Dr Kirsch, adapting personal characteristics in the "age of stress" (in addition to reducing stress), is the best option we have as a society. One of the most important resilience factors here is "physical activity". In the area of the hippocampus, "physical activity" is associated with a reduction in the neurotoxicity of stress hormones. Another resilience factor is spending time in nature. Another therapy option is Neurexan. This is a mixture of passion flower, oats, zinc salt, valeric acid and coffee seeds. In a study, Neurexan reduced the stress response in the brain's stress network.1

Conclusion for medical practice

Chronic everyday stress leads to:

  1. Kirsch Peter, Prof. Dr. med., Original Title: "Stress im Alltag – Neurobiologische Grundlagen und gesundheitliche Folgen, Industrie-Symposium "Schlafstörungen im Stresszeitalter", [Stress in everyday life - neurobiological basics and health consequences, Industry Symposium "Sleep disorders in the age of stress"], 130. Kongress der Deutschen Gesellschaft für Innere Medizin [130th Congress of the German Society of Internal Medicine], Wiesbaden, 14 to 16 April. 2024.