Stress And The Immune System: How Are They Related?

Many authors have been interested in the relationship between stress and the immune system. How do stressful situations affect our defenses?

Stress is usually associated with a pathological state. However, it alludes to a reaction of the human being to threatening situations or excessive demand. Thus, they can be at the service of the survival of the subject and the species.

Stress and the immune system

The constant changes to which we are subjected on a daily basis can take their toll on us. Economic difficulties, work demands or negative life events that occur can generate an inadequate maladjustment on the part of our body. When these reactions are prolonged in time, an overload is produced in the body that can trigger health problems. This is known as distress.

On the contrary, when an individual generates well-controlled and effective responses that allow him a good adaptation, this is called stress.

How can the body respond to these demands? We have already mentioned previously how the stress response occurs. It involved different systems in a systemic and complex relationship. This network is formed by the interaction that involves the psychism and the nervous, endocrine and immune systems, as something different from the sum of these systems.

In this sense, Ader (2003) explains:

“It is now clear that immune function is influenced by the autonomic activity of the nervous system and by the release of neuroendocrine substances from the pituitary. Conversely, cytokines and hormones released by the activated immune system influence endocrine and nervous system processes. Regulatory peptides and receptors, confined to the brain, are expressed by both the immune systems and the nervous system that allow each system to monitor and modulate the activities of the other ”.

History of psychoneuroimmunology

It is for the first time, in 1981, when the scientist Robert Ader presented the term psychoneuroimmunology. He defines it as the scientific discipline that studies the interaction between behavior, neural and endocrine functions, and immune processes.

Prior to this definition, the classical conception of the immune system was to consider it as a self-regulatory and autonomous defense system. In the 1920s, research began in Russia on the classical conditioning of immune responses. Somewhat later, in the 1950s, Rasmussen and his collaborators formed the first research team in stress and infectious diseases.

However, it is not until the 1970s that John Hadden intuits this relationship between stress and the immune system. Specifically, it refers to the association between the sympathetic nervous system and the immune system.

Ader’s experiments

Thus, in 1981, Robert Ader presented the first manual and, with it, the beginning of the discipline of psychoneuroimmunology . His experiments with rodents focused on taste aversion using classical conditioning. In his experiments, he performed a previous training phase, where the control group was treated with placebo and the experimental group with cyclophosphamide.

In the first, no abnormal response was produced, however, the experimental group presented nausea and immunosuppression. In the second phase, the scientist administered saccharin to the two groups. Thus, the control group continued without producing any abnormal response, while the experimental group presented aversive taste conditioning and immunosuppression.

Other authors, such as George Solomon, also entered the world of psychoneuroimmunology. Specifically, Solomon studied autoimmunity and psychological well-being. However, unlike Ader, Solomon did not continue his studies. This caused that his findings did not become famous. Besedovsky was another of the authors who was interested in the relationships of the immune system. He considered this as a sensory organ.

Current concept of psychoneuroimmunology

Currently, communication between the immune system and the brain is considered to be two-way. The changes that occur in the immune system are an explanatory mechanism by which psychosocial factors influence health and disease.

Our species is under constant threat from a large number of pathogens. In this sense, the tasks of the immune system are:

  • Quickly recognize cell degeneration and prevent cancer development
  • Ensuring the integrity of the body

In this way, when faced with stress, the body reacts with a response that may or may not be adaptive. No one doubts that stress and the immune system are in constant contact; a communication on which our quality of life depends, to a large extent.