Medically reviewed by Suzanne Falck, M.D., FACP — Written by Jill Seladi-Schulman, Ph.D. — Updated on September 17, 2018 What is psychoneuroimmunology? Psychoneuroimmunology (PNI) is a relatively new field of study that looks at the interactions between your central nervous system (CNS) and your immune system. Researchers know that our CNS and immune system can communicate with each other, but they only recently started to understand how they do it and what it means for our health. The nerves in your brain and spinal cord make up your CNS, while your immune system is made up of organs and cells that defend your body against infection. Both systems produce small molecules and proteins that can act as messengers between the two systems. In your CNS, these messengers include hormones and neurotransmitters. Your immune system, on the other hand, uses proteins called cytokines to communicate with your CNS. There’s plenty of existing research about the effects of stress on the immune system. Many of these studies focus on the release of cytokines in response to both physical and psychological stress. A cytokine is a small protein that’s released by cells, especially those in your immune system. There are many types of cytokines, but the ones that are generally stimulated by stress are called pro-inflammatory cytokines. Under normal circumstances, your body releases pro-inflammatory cytokines in response to an infection or injury to help destroy germs or repair tissue. When you’re physically or emotionally stressed, your body also releases certain hormones, including epinephrine (adrenaline). These hormones can bind to specific receptors that signal for the production of pro-inflammatory cytokines. Here’s a look at some of the recent research and discussions around PNI in the medical community: INSERT LONG LIST FORMAT:
What does all of this new knowledge mean for our health? Keep reading to learn more about the role that PNI plays in several common conditions. PsoriasisPsoriasis is a great example of how your immune system, CNS, mental health, and stress levels are all intertwined. It’s a chronic condition that causes your skin cells to grow too quickly. Your body usually sheds extra skin cells, but if you have psoriasis, these extra cells build up on your skin’s surface. This can lead to intense itching and pain. The overgrowth of skin cells in psoriasis is due to the release of cytokines from your immune system. We know that psychological stress may worsen or trigger episodes of psoriasis. Indeed, people with psoriasis tend to have increased levels of cortisol, a stress hormone. Your hypothalamus, which is part of your CNS, is responsible for cortisol production. When it senses stressors, it signals your nearby pituitary gland, which signals for cortisol production. This, in turn, can trigger the release of pro-inflammatory cytokines by your immune system. These cytokines then trigger an overgrowth of skin cells. In addition, people with psoriasis often report having psychological conditions, such as depression, increased stress, and suicidal thoughts. Previous research has linked an increase in cytokine levels with major depression. There’s currently no cure for psoriasis, but new developments in the field of PNI could change this in the future. In the meantime, here’s how to manage it at home. CancerA 2013 review of many studies exploring the relationship between PNI and cancer found evidence to suggest that:
Coronary artery diseaseA review from 2010 looking at the relationship between stress, immune function, and coronary artery disease echoed other studies suggesting that psychological stress increases the production of pro-inflammatory cytokines. This increase in pro-inflammatory cytokines is associated with an increase in heart rate and blood pressure. In addition, the production of cytokines by your immune system promotes feelings of sickness or fatigue. According to this review, this reaction isn’t immediately harmful. However, long-term stress and cytokine production may contribute to the development of cardiac disease. PNI is a rapidly growing field of study that looks at the relationship between your CNS and immune system. While some of the research has raised more questions than answers, researchers now know that both physical and emotional stress can have a very real effect on your immune system. The future of PNI will likely look at how this relationship impacts certain conditions, including cancer and psoriasis. It may even point researchers in the direction of long-awaited cures for both of these conditions, along with many others. Last medically reviewed on January 26, 2018 Healthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.
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