This discipline integrates different sciences to improve the quality of life of patients.
Studying the relationships between the different biological systems of the body, such as the immune system or the endocrine system, and the brain (and the human mind) is the main objective of a discipline called psychoneuroendocrinoimmunology.
This science helps us understand important aspects such as the way in which psychological factors can influence the evolution or course of a disease, or how stress affects our quality of life.
In this article we explain what psychoneuroendocrinoimmunology is and what it studies, and we give you the keys to understand how stress affects our immune system and what impact the mind has on our health.
What is psychoneuroendocrine immunology and what does it study?
Psychoneuroendocrinoimmunology, also known as psychoneuroimmunology, is the discipline that studies the interactions between behavioral, neuronal, endocrine and immune processes. Researchers know that the nervous system and the immune system can communicate with each other, but it was not until relatively recently that we began to understand how they do so and what it means for our health.
One of the basic aspects that this discipline assumes is that mind and body are two inseparable entities. It follows that stress affects the body’s ability to resist disease. Furthermore, we know that the brain influences all kinds of physiological processes that were once thought to be unregulated centrally.
There are effects of psychological factors in many diseases, such as rheumatoid arthritis, diabetes, hypertension, heart disease or inflammatory bowel disease, among others. The objective of psychoneuroendocrinoimmunology is to study precisely what role the physiological functioning of the neuroimmune system plays in health and disease, as well as the physical, chemical and physiological characteristics of the components of the immune system.
Connections between the brain and the immune system
As the field of psychoneuroendocrine immunology grows and develops, many discrete pathways of communication between psychological factors and the immune system are discovered.
In recent decades, the depth of integration between the nervous system and the immune system has been slowly diminishing, and one of the key aspects has been to better understand the functioning of the hypothalamic-pituitary-adrenal (HPA) axis and the impact that the psychological stress has on this particular system.
The hypothalamic-pituitary-adrenal axis (HPA)
The HPA axis involves three small endocrine glands that secrete hormones directly into the blood. The glands in question are the hypothalamus and pituitary, which are neurological neighbors, and the [adrenal glands] (adrenal glands), located in the upper part of the kidneys. This triad of tissues controls reactions to stress and regulates processes such as digestion, the immune system, sexuality, mood, and energy use.
A notable chemical at work on the HPA axis is corticotropin-releasing hormone (CRH). The hypothalamus releases CRH in response to stress, illness, exercise, cortisol in the blood, and sleep-wake cycles. It peaks shortly after waking up and slowly declines throughout the rest of the day.
However, in a stressed individual, cortisol levels rise for prolonged periods of time. During stress, the body believes it is in imminent danger, so cortisol triggers a series of metabolic changes to ensure that there is enough energy available in case fight or flight is necessary. One of these energy saving tactics is to suppress the metabolically costly immune system, saving vital glucose for the life-threatening event.
Of course, in modern humans, stress levels can rise for various reasons, and very few of these situations pose a real threat to survival and life. In this way, that continuous stress can reduce the capacities of the immune system, with negative consequences for our health.
On the contrary, there is evidence that oxytocin, produced during positive social interactions, helps to dampen the activity of the HPA axis. And what’s more, this has been shown to promote health benefits, such as increasing the speed of wound healing.
Different stress, different immune system
In a discipline like psychoneuroendocrinoimmunology, clinical research is very important. In a meta-analysis of 300 empirical studies, it was found that certain types of stress alter different aspects of the immune system. Brief stressors, such as exams, were compared to chronic stressors, events that change a person’s life, such as caring for a loved one with dementia.
Brief stressors tend to suppress cellular immunity (the kind that deals with cellular invaders, like viruses) while preserving humoral immunity (typically deals with pathogens outside of cells, like parasites and bacteria ). On the other hand, chronic stressors tended to suppress both types of immunity.
Stress has a measurable effect on the strength of the immune system, and therefore its ability to protect us. In a very real way, managing stress levels can help maximize the power of the immune system. Research has shown time and again that people in stressful situations have measurable changes in physical responses to injuries. Whether it is slow wound healing, a higher incidence of infections, or a worse prognosis for cancer survival.
For many years, the immune system has been considered an autonomous and independent mechanism, but as we now know, this is not the case. The brain communicates regularly with the cells of the immune system and vice versa, which tells us that stress is both psychological and physical. Therefore, learning to control stress is an important skill if we want to prevent and reduce the problems associated with many diseases and have our immune system in optimal conditions.
The impact of the mind on our health
The effect of psychological factors on our health can be really significant. In a discipline like psychoneuroendocrinoimmunology, an attempt has been made to investigate how the “mind” and cognition influence our immune system and our health in general, and the results can be surprising.
Next, we are going to see some examples of what is known so far in this regard:
1. The psychological grief
Stories of recently deceased people who die shortly after their partner are quite common, and they are not usually apocryphal. In a recent study that followed more than 90,000 widowed individuals, it was found that during the first week after bereavement, mortality was twice the expected rate.
2. The intestine
At present it is quite well established that there is a strong association between sustained stressful life events and the appearance of symptoms in functional gastrointestinal disorders, inflammatory bowel diseases and the so-called irritable bowel syndrome.
Although there is no scientific evidence that directly links positive thinking with cancer reduction, health professionals who work with cancer patients know very well that the patient’s perspective, attitude, and motivation, and their quantity and quality of support psychological can greatly affect the outcome of your illness.
4. HIV (human immunodeficiency virus)
Research has found significant evidence that elevated levels of stress and decreased social support accelerate the progression of certain diseases, including HIV
5. Skin problems
We know that conditions such as psoriasis, eczema and asthma are conditioned by psychological aspects. The effect of daily stress can cause a person to have flare-ups or make their symptoms worse.
6. Wound healing
The speed at which a surgical patient heals has also been related to psychological factors. For example, increased levels of fear or distress before surgery have been associated with worse outcomes, including longer hospital stays, more postoperative complications, and higher rates of rehospitalization.
Also, in a study in patients with chronic lower leg wounds, those who reported higher levels of depression and anxiety showed significantly delayed healing.
Kanba, S. (2001). Psychoneuroimmunology: A Dialogue between the Brain and Immune System. Journal of International Society of Life Information Science, 19 (1), 141-145.
Pérez de Alejo Rodríguez, LM, Moré Chang, CX, González Álvarez, Y., & Alemán Zamora, A. (2019). Psychoneuroendocrinoimmunology: claim for an integral vision in medical studies. Edumecentro, 11 (3), 254-261.
Sivik, T., Byrne, D., Lipsitt, DR, Christodoulou, GN, & Dienstfrey, H. (2003). Psycho-Neuro-Endocrine-Immunology (PNEI): A Common Language for the Whole Human Body. Psychotherapy and Psychosomatics, 72 (5), 292.