2.18 What is Psychoneuroimmunology? – Definition & Impact

Jan 18, 2020 | ch2 Biological Bases of Behaviour, Courses, Intro to Psychology

Psychoneuroimmunology (PNI) is the study of how the brain, nervous system, and the immune system impact each other. Applications include how stress leads to illness and how chronic inflammation can lead to cardiovascular problems and cancer.

What Is Psychoneuroimmunology?

Did your mother ever tell you to be sure to bundle up properly in the winter so you would not get sick? Well, mine did, but I never listened because I thought only germs, not being cold, could make me sick. Yet every time I shivered with an inadequate coat, I got sick. A new science is proving all those moms right.

Psychoneuroimmunology (PNI) – and its newer name psychoneuroendoimmunology (PNEI) – is an exciting subject in health today but that jaw-breaker of a name is daunting. Let’s break it down, and you’ll see how simple it is:

  • ‘psycho-‘ means thoughts and emotions
  • ‘-neuro-‘ means that the physical brain is involved
  • ‘-endo-‘ brings in the endocrine system
  • ‘-immunology’ explains how your immune system protects you from illness

PNI researchers study how your emotions and thoughts impact your brain, hormones, and nervous system and also your immune system’s ability to protect you. It can also work the other way – changes in the immune and endocrine systems create changes in your nervous system which lead to changes in your emotions. Let’s see how this interaction works.

Why Are Researchers Excited About Studying PNI?

For a long time, the idea that your emotions could impact your physical health was considered a myth believed by people who supported holistic health in place of traditional medicine. Over the past 25 years, solid research has proven that prolonged stress and specific traumatic experiences change the biochemistry of your brain and your hormones.

Stressful emotions also reduce the numbers and effectiveness of immune system cells, including

  • The inflammation response which is part of your non-specific protection
  • The t cells that directly attack invaders and the Natural Killer (NK) t-cells that rid you of cancers
  • The macrophages that also attack directly
  • The cells and processes, including cytokines, that fuel chronic inflammation – a risk factor for cardiovascular disease and cancer

People who were abused or neglected as children can have permanent changes in their brain chemistry and immune response as a result. Trauma survivors, like military veterans, natural disaster and assault victims, and those who work in first responder roles, have higher than expected incidences of both infectious illnesses (because their immune response to viruses is reduced) and cancer.

Even loneliness can be the cause of immune system suppression that can lead to illness. PNI also studies how positive emotions can bolster both immune and endocrine system responses. The interactions work in the other direction as well, with many disease sufferers prone to developing clinical depression in response to lowered hormone levels and chronic inflammation. Studies of cancer victims and other disease-sufferers who receive psychotherapy and group support show that these interventions in emotional health can have an impact on physical health.

How Is PNI Research Changing Medical and Psychological Practice?

Psychoneuroimmunology encourages primary care medical providers to consider their patient’s stress levels and emotional health when assessing a health question. It has convinced insurance companies to support hypnotherapy, acupuncture, massage, and related therapies as important disease-prevention and treatment strategies. All of these new therapies are known to activate immune response either through impacting the nervous system or through reducing anxiety and stressful emotions.

PNI research validates the efforts of caring traditional medical practitioners who try to treat the whole person, not just a disease or symptom. Reputable holistic health practitioners have seen clinical evidence of mind-body interactions but lacked the facilities to conduct rigorous scientific studies of how these systems interact.

PNI allows doctors to incorporate holistic health into their traditional practice, knowing that the underlying assumptions of connection between emotions, immune systems, and endocrine processes are soundly rooted in science. It also reminds psychologists to recommend medical tests of the endocrine and immune system when evaluating feelings and emotions.

We know now that the road to lifelong health includes our emotions as well as our checkups. Don’t go out in the winter without a hat and take steps to reduce stress and loneliness! It’s just what the doctor ordered.

Lesson Summary

Psychoneuroimmunology and psychoneuroendoimmunology explore how your emotions, your immune and endocrine systems, and your nervous system influence and impact each other. The three systems play their part in keeping you well and in responding to illnesses. Research indicates that emotional stress lowers the number of immune system cells your body can marshal to defeat an illness, that a lowered immune system can lead to depression, and that when the immune system engages, changes occur in the nervous system as well.

Traditional medicine as well as holistic medicine is now based on a known mind-body connection. PNI medical and psychological researchers are showing traditional doctors how important the interaction between these three systems is, allowing them to better diagnose and treat medical problems.

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