Psychoneuroimmunology: Meaning and Significance

The immune system is the complex network of organs that gives resistance to infection and toxins. It destroys invading organisms like bacteria and viruses and removes damaged or dead cells. The immune system also helps to control inflammation. When a foreign substance enters the body, the immune system recognizes it as being different from the body's cells and tissues. It produces antibodies to fight the invader. These antibodies attach to the foreign substance, making it easier for the white blood cells to destroy. It includes the thymus, bone marrow, and lymph nodes.

What is Psychoneuroimmunology?

"Psychoneuroimmunology studies the connections between stress, the body's immune system, and illness." The term "stress" is used in several different ways. In physiology, it is a physical or emotional force or pressure that can cause harm to the body. In psychology, it refers to people's responses to events that challenge them. A person under stress releases hormones such as adrenaline and cortisol. These hormones help the body cope with stressors. However, if they are constantly exposed to stressors, cortisol can cause changes such as immune system suppression and a reduction in their ability to fight infection and disease. For example, when a person is stressed, they are more likely to get a headache, which can lead to a migraine if it lasts too long. If a person already suffers from an illness, stress can change the course of its advancement.

A recent study revealed that corticosteroids stimulate the production of cytokines, proteins that attach to receptors throughout the body. Cytokines, another important factor in the immune system, assist combat infection under moderate stress levels. However, if stress persists and more corticosteroids are produced, the increased synthesis and distribution of cytokines causes chronic inflammation throughout the body, which increases susceptibility to heart disease, stroke, cancer, and other disorders. In addition to weakening our immune system, stress can also lead to several other physical and emotional problems, including−

Many studies have established a relationship between chronic stress and physical health problems like cold, flu, asthma, heart disease, obesity, and diabetes.

Types of Stress

There are two types of stress: eustress and distress.

  • Eustress is a type of positive stress associated with feeling energetic and enthusiastic. This type of stress can help achieve goals and can improve productivity.

  • Distress is a type of negative stress that is associated with feelings of anxiety, frustration, and irritability. This type of stress can be harmful and lead to health problems.

Stress can also affect the production of neurotransmitters, which help regulate our moods and emotions. Under high levels of stress, neurotransmitters like serotonin and dopamine get depleted, which leads to feelings of depression and anxiety. Two important stress-signaling networks that contribute to immunological dysregulation are the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis. When the brain perceives a stressful environment, it activates the HPA axis and the sympathetic-adrenal medullary axis (SAM), causing the production of immune-modulating hormones such as adrenocorticotropic hormone (ACTH), and cortisol, growth hormone, prolactin, epinephrine, and norepinephrine.

In the study published in the Nature Neuroscience journal, scientists found that when rats were given low doses of cortisol, they were more likely to take risks for reward. The researchers suggest that cortisol may increase the "reward value" of things one finds pleasurable, such as food and drugs.

They suggest that this could help in describing why people with high levels of cortisol may be more likely to take risks to get rewards. The study helped in understanding the relationship between stress and inflammatory reactions, a key focus of the discipline of psychoneuroimmunology. Acute inflammation is an adaptive reaction to physical injury or disease; chronic and persistent inflammation is harmful to health.

When it comes to the nervous system, the immune system plays a vital role in ensuring that messages are relayed properly between different parts of the body. Stress impacts the immune system of a human being. There is a large and growing body of research that suggests chronic stress can have a negative impact on the immune system. The immune system is responsible for protecting the body against infection and disease; when it is compromised, individuals are more susceptible to illness and infection. Chronic stress has been shown to decrease the number of immune cells in the body, including white blood cells, which are essential for fighting infection. Additionally, stress can cause the body to produce more of the hormone cortisol, which can suppress the immune system.

Ways to Cope

Though it is very difficult to avoid all stress, but it can be managed through change in life-style such as regular exercise, yoga, eating healthy food, etc.

Following are some of the effective strategies that help to manage the stress−

Some others are -


Permanency of stress may increase the risk for heart disease, stroke, diabetes, and other chronic illnesses. Also, stress can lead to sleep, digestion, and memory problems. Physical health is not the only thing that can be impacted by stress; our mental health can also be affected. Stress can lead to feelings of anxiety or depression and can worsen preexisting mental health conditions. It can make it difficult to focus, think clearly, or make decisions. The immune system constantly works to protect the body from harmful bacteria, viruses, and other foreign invaders.

Updated on: 25-Nov-2022


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