What is Psychoneuroimmunology (PNI)
Hippocrates, the father of modern day medicine, suggested “for this is the great error of our day that the physicians separate the soul from the body.” Until the 17th Century medical science gave equal credence to physical and holistic approaches to health. Vitalistic and allopathic approaches to health were researched and applied equally until Rene Descartes proposed what was to become the Cartesian model of allopathic medicine “two distinct and separate substances in the world: matter, which behaved according to physical laws and spirit which was dimensionless and immaterial.” This new model created the belief that mind and body were unrelated and this view was solidified by assertions such as those of Koch in the 19th Century that “every disease had a simple, specific cause, germs.”
In the last 100 years medical science has made more advances than in the combined years since its inception. Each new scientific discovery has led to an increasingly reductionist view, dissecting findings down to the molecular and sub-atomic level in the search for answers. Unfortunately, this approach moves us further away from the indisputable fact that regardless of how sectioned off research may be in socioeconomical and political terms, each discovery impacts on a much larger scale, at every level in the body as a whole and complex organism.
The time has come for a paradigm shift in our approach to health and medicine and in the last 20 years a new science is leading the way. Psychoneuroimmunology is the science of the body as a complex network of feedback loops linking each individual system to the others. Using the latest technology it has been proven without doubt that every system in our bodies, the brain, the nervous system, the endocrine system, the immune system and most importantly our mind and consciousness are all linked by combined networks of physical connections such as nerves, chemical messengers such as hormones and other information substances such as neuropeptides and immune modulators. (Figure 1) The vast network of positive and negative feedback loops linking all of these systems to each other acts to regulate every aspect of our physical and mental functioning with exquisite precision. Data from this research means that we can no longer categorize disease states as purely physical or mental and we can no longer assume that symptoms manifesting in a specific organ or system originate or can be treated there. This new information means that we need to reassess our approach to the management of health, illness and disease.
Psychoneuroimmunology (PNI)- the future of diagnostic medicine
The New Paradigm
In order for us to fully comprehend the impact of psychoneuroimmunology we have to view health not as an absolute but rather as a sliding scale along which we move backward and forward depending upon the influencing factors in our lives. In physiological terms, a homeodynamic system that is constantly attempting to reach a maximally coherent state between the systems that equates to Optimum Health. (Figure 2) The goals of optimum health being increased quality of life, increased health, increased longevity and decreased disease morbidity and mortality.
Figure 3 illustrates the influencing factors that are common to all and that affect the balance between a positive and negative health index. Each of these factors can act at any point along the physiological coherence line in either a positive or a negative way.
In accepting this new paradigm we must also accept that the way we attempt to maintain health and treat disease must change. In order for this to happen we must first identify the conditions that lead to a negative health index.
Disease and ill health are the culmination of multiple factors that reduce the coherence between our body systems resulting in the predominance of negative feedback and a state of physiological stress. When in this state our bodies become more susceptible to the negative effects of influencing factors. This is often a long process in which the cumulative effects of low grade stressors, each of which may be below the threshold that they alone could cause significant ill health, combine to produce an increased susceptibility to one or several physiological stressors. This increased susceptibility manifests as an increased activity in negative feedback pathways between the different body systems and is compounded by a reduction in the stimulatory and positive feedback pathways. The absence of positive external influencing factors further accentuates this effect.
Evidence supporting this hypothesis comes from scientific studies and there is much anecdotal evidence to lend further support. The multiple stressor model offers an explanation as to why not all people who are genetically predisposed succumb to disease, why not all people exposed to carcinogens develop cancer and why pathogens affect different people with differing degrees of severity. Using the networked system model a possible explanation can be offered as to why “miracle cures” work for some and not others through the proven impact of mental attitude on physiological processes.
In terms of evolution our bodies evolve more slowly than our cultural and social environments and currently we find ourselves exposed to multiple assaults on our physiological and psychological health. In attempting to redress this balance we must first identify predisposing factors that make us susceptible to stressors, the stressors themselves and the steps we must take to protect against the effects of these. This approach requires the combination of science, medicine and lifestyle in order to fully address each aspect of disease susceptibility and health maintenance. Most of all it requires a shift from reactive to pro-active healthcare and health management.