Contributor: Christine Hodgson, MSN, RN, CPNP-PC

In the first week of my nursing Ph.D. program, I heard a brief presentation from a professor who taught “psychoneuroimmunology.”  I had never heard that word, but I knew I had to take that class.  I was entering my Ph.D. journey after a long career as a primary care pediatric nurse practitioner. I had started to feel a thirst for knowledge about the mind-body-spirit connection, how it relates to wellness, and how we can implement integrative healthcare across cultures. Fortunately, my first year included a class on nursing theory development and evaluation, so I was prepared to enter this mysterious class with my newly solidified personal worldview, epistemology, ontology, and favorite nursing theories.

Psychoneuroimmunology (PNI) did not strike me as a theory at first. I had just finished refresher classes in endocrinology and immunology, wherein having an old textbook didn’t matter too much because these reductionist sciences were slowly changing. On the other hand, I quickly learned that PNI was a young theory about bi-directional communication among the mind-brain-immune-endocrine systems that was gaining an evidence base and interest across many disciplines. My professor, Dr. Pace, noted that he loved teaching nurses because we “are so good with theories.” I stopped to think about how PNI contrasted with the nursing theories I had learned…as well as how it aligned with nursing theories (more on that later).

What is PNI?

PNI is a re-emergence of ancient beliefs that organisms are integrated systems (Daruna, 2012, p.13). Robert Ader was a psychologist who, along with Nicholas Cohen, originated PNI and advanced the field of mind-body science in 1980 (Daruna, 2012, p.21). Ader’s discovery that rats could be trained to have a particular immune response came at a time when biomedical science was ready for a new holistic theory. PNI has established that the immune system crosses the blood-brain barrier affecting physical, cognitive, psychological, and behavioral functions. Probably the most well-known model within PNI is that of the Stress Response (Pace, 2020, October 26). Acute psychological or physical stress activates pro-inflammatory cytokines such as IL-1 and IL-6. Acute stress also shifts the body’s homeostasis to a sympathetic (fight or flight) response and triggers the hypothalamus-pituitary-adrenal axis (HPA) to release cortisol. These acute immune mechanisms help protect the human organism in the short term. However, chronic or cumulative stress can lead to inflammation and cortisol dysfunction. In addition to physiologic changes, cytokines affect neurotransmitters leading to changes in cognition and behavior. Pace summarized how multiple complex pathways related to stress and inflammation increase the risk for physical and mental illness throughout life.

What are PNI Interventions?

We can measure immune biomarkers through blood or saliva, so scientists have been able to test interventions that prevent or disrupt the stress-immune pathway. Mindfulness, meditation, nutrition, exercise, sleep, and counseling are just a few PNI interventions that have an evidence base for various illnesses (Pace, 2020, November 23). Nursing practice already values these nurturing and accessible tools, so we are all PNI practitioners.

PNI and Nursing Theory

I believe our very first nurse theorist, Florence Nightingale, would have appreciated the tenets of PNI. Not only did Nightingale’s prescient focus on infection control address the immune system’s role in health, but her methodical and statistical approach to nursing also laid the foundation for complex knowledge discovery (Nelson & Rafferty, 2011). Grand nursing theories that followed Nightingale’s work included those in the integrative-interactive paradigm, which views a patient as an interactive whole capable of a multitude of adaptation responses to their environment. Examples of integrative-interactive conceptual models include Sr. Callista Roy’s adaptation model, Betty Neuman’s systems model, and Barbara Dossey’s theory of integral nursing (Smith & Parker, 2015, p. 88). The field of PNI is producing voluminous empiric evidence that the human body is an interconnected whole, which supports these holistic nursing theories.

For a more specific example of how a nursing theory could guide a hypothetical PNI research study about the long-term effects of stress, I will refer to Betty Neuman’s systems model (NSM) (Lowry & Aylward, 2015) and provide a conceptual-theoretical-empirical structure (Gigliotti & Manister, 2012). I hypothesize, based on previous research (Felitti et al., 1998), that adverse childhood events (ACEs) cause inflammation that leads to cardiovascular disease (CVD) later in life, and smoking behaviors mediate the relationship. NSM is a model about a client’s adaptation to internal or external stressors and includes the client concepts of stressor, invasion of the normal line of defense, lines of resistance, and core response (Lowry & Aylward, 2015). The theoretical linkages of PNI in my study are ACEs, cortisol response via the HPA axis; inflammation/cognitive changes/maladaptive behaviors; and cardiovascular disease, respectively. The empirical measures of these links are a self-report ACE questionnaire; salivary cortisol levels; attenuated cortisol response measures/depression and anxiety symptom survey; and blood pressure/cholesterol/smoking behaviors, respectively. Here physiological and psychological variables of the hypothesis are directly measured, allowing us to understand the more abstract concepts of the NSM and their relationships to one another. The NSM also includes a concept of intervention as prevention that aligns with the wellness focus of PNI.

Nursing Knowledge Development and the Future of PNI

Despite congruence with existing nursing theories, incorporating PNI in developing a new middle-range nursing theory could move down the ladder of abstraction to a more concrete explanation of concepts (Smith & Liehr, 2018, chapter 2). For example, a middle-range PNI nursing theory might focus on the prevention and treatment of ACEs with children and their families. PNI emphasizes the natural healing processes of humans, is adaptable to the personalized or the public health level, and even has economic benefits to a healthcare system (Daruna, 2012, p. 280-83). If we adopt a nursing PNI conceptual model for wellness and prevention, we can improve outcomes such as depression, diabetes, cancer, heart disease, autoimmune diseases, and more.

Two years after my introduction to the term psychoneuroimmunology, I am preparing for my comprehensive exams. As I reflect on my Ph.D. curriculum, I realize the degree to which nursing theories and PNI have already informed my nursing research and practice. I hope to contribute to a future where nurses, guided by theory, have more understanding and tools to care for the complex human being…but first, back to studying!

References

Daruna, J. H. (2012). Introduction to psychoneuroimmunology. (2nd ed.) Elsevier, Inc.

Felitti, V. J., Anda, R. F., Nordenberg, D., Williamson, D. F., Spitz, A. M., Edwards, V., Koss, M. P., & Marks, J. S. (1998). Relationship of childhood abuse and household dysfunction to many of the leading causes of death in adults. The Adverse Childhood Experiences (ACE) Study. American Journal of Preventive Medicine, 14(4), 245-258. https://doi.org/10.1016/S0749-3797(98)00017-8

Gigliotti, E., & Manister, N. N. (2012). A beginner’s guide to writing the nursing conceptual model-based theoretical rationale. Nursing Science Quarterly, 25(4), 301–306. https://doi.org/10.1177/0894318412457060

Lowry, L. W. & Alyward, P. D. (2015). Betty Neuman’s Systems Model. In M. C. Smith & M. E. Parker (Eds.) Nursing theories & nursing practice. (4^th ed., pp. 165-181) F. A. Davis Company.

Nelson, A. M. & Rafferty, S. (Eds). (2011). Notes on Nightingale: the influence and legacy of a nursing icon. (1st ed.) Cornell University.

Pace, T. W. W. (2020, October 26). Stress as a risk factor for illness. [Powerpoint slides]. University of Arizona College of Nursing, Psychoneuroimmunology: Foundations and Clinical Implications. D2L: https://d2l.arizona.edu/d2l/home

Pace, T. W. W. (2020, November 23). PNI mechanisms of wellness I. [Powerpoint slides]. University of Arizona College of Nursing, Psychoneuroimmunology: Foundations and Clinical Implications. D2L: https://d2l.arizona.edu/d2l/home

Smith, M. J.  & Liehr, P. R. (2018). Middle range theory for nursing. (4th ed.). Springer.

Smith, M. C. & Parker, M. E. (Eds.) (2015). Nursing theories & nursing practice. (4^th ed.). F. A. Davis Company.

About Christine Hodgson

Christine Hodgson has been a pediatric nurse practitioner for over 20 years. She currently works in school-based health clinics, including one on an Indian reservation. She lives in Montana with her husband who is a pediatrician, three sons, and two golden retrievers. She loves to hike, bike and ski in the mountains, travel and read. She plans to study the resilience of indigenous children around the globe.