by Maria Popova
I had lived thirty good years before enduring my first food poisoning — odds quite fortunate in the grand scheme of things, but miserably unfortunate in the immediate experience of it. I found myself completely incapacitated to erect the pillars of my daily life — too cognitively foggy to read and write, too physically weak to work out or even meditate. The temporary disability soon elevated the assault on my mind and body to a new height of anguish: an intense experience of stress. Even as I consoled myself with Nabokov’s exceptionally florid account of food poisoning, I couldn’t shake the overwhelming malaise that had engulfed me — somehow, a physical illness had completely colored my psychoemotional reality.
This experience, of course, is far from uncommon. Long before scientists began shedding light on how our minds and bodies actually affect one another, an intuitive understanding of this dialogue between the body and the emotions, or feelings, emerged and permeated our very language: We use “feeling sick” as a grab-bag term for both the sensory symptoms — fever, fatigue, nausea — and the psychological malaise, woven of emotions like sadness and apathy.
Pre-modern medicine, in fact, has recognized this link between disease and emotion for millennia. Ancient Greek, Roman, and Indian Ayurvedic physicians all enlisted the theory of the four humors — blood, yellow bile, black bile, and phlegm — in their healing practices, believing that imbalances in these four visible secretions of the body caused disease and were themselves often caused by the emotions. These beliefs are fossilized in our present language — melancholy comes from the Latin words for “black” (melan) and “bitter bile” (choler), and we think of a melancholic person as gloomy or embittered; a phlegmatic person is languid and impassive, for phlegm makes one lethargic.
And then French philosopher and mathematician René Descartes came along in the seventeenth century, taking it upon himself to eradicate the superstitions that fueled the religious wars of the era by planting the seed of rationalism. But the very tenets that laid the foundation of modern science — the idea that truth comes only from what can be visibly ascertained and proven beyond doubt — severed this link between the physical body and the emotions; those mysterious and fleeting forces, the biological basis of which the tools of modern neuroscience are only just beginning to understand, seemed to exist entirely outside the realm of what could be examined with the tools of rationalism.
For nearly three centuries, the idea that our emotions could impact our physical health remained scientific taboo — setting out to fight one type of dogma, Descartes had inadvertently created another, which we’re only just beginning to shake off. It was only in the 1950s that Austrian-Canadian physician and physiologist Hans Selye pioneered the notion of stress as we now know it today, drawing the scientific community’s attention to the effects of stress on physical health and popularizing the concept around the world. (In addition to his scientific dedication, Selye also understood the branding component of any successful movement and worked tirelessly to include the word itself in dictionaries around the world; today, “stress” is perhaps the word pronounced most similarly in the greatest number of major languages.)
But no researcher has done more to illuminate the invisible threads that weave mind and body together than Dr. Esther Sternberg. Her groundbreaking work on the link between the central nervous system and the immune system, exploring how immune molecules made in the blood can trigger brain function that profoundly affects our emotions, has revolutionized our understanding of the integrated being we call a human self. In the immeasurably revelatory The Balance Within: The Science Connecting Health and Emotions, Sternberg examines the interplay of our emotions and our physical health, mediated by that seemingly nebulous yet, it turns out, remarkably concrete experience called stress.
With an eye to modern medicine’s advances in cellular and molecular biology, which have made it possible to measure how our nervous system and our hormones affect our susceptibility to diseases as varied as depression, arthritis, AIDS, and chronic fatigue syndrome, Sternberg writes:
By parsing these chemical intermediaries, we can begin to understand the biological underpinnings of how emotions affect diseases…
The same parts of the brain that control the stress response … play an important role in susceptibility and resistance to inflammatory diseases such as arthritis. And since it is these parts of the brain that also play a role in depression, we can begin to understand why it is that many patients with inflammatory diseases may also experience depression at different times in their lives… Rather than seeing the psyche as the source of such illnesses, we are discovering that while feelings don’t directly cause or cure disease, the biological mechanisms underlying them may cause or contribute to disease. Thus, many of the nerve pathways and molecules underlying both psychological responses and inflammatory disease are the same, making predisposition to one set of illnesses likely to go along with predisposition to the other. The questions need to be rephrased, therefore, to ask which of the many components that work together to create emotions also affect that other constellation of biological events, immune responses, which come together to fight or to cause disease. Rather than asking if depressing thoughts can cause an illness of the body, we need to ask what the molecules and nerve pathways are that cause depressing thoughts. And then we need to ask whether these affect the cells and molecules that cause disease.
We are even beginning to sort out how emotional memories reach the parts of the brain that control the hormonal stress response, and how such emotions can ultimately affect the workings of the immune system and thus affect illnesses as disparate as arthritis and cancer. We are also beginning to piece together how signals from the immune system can affect the brain and the emotional and physical responses it controls: the molecular basis of feeling sick. In all this, the boundaries between mind and body are beginning to blur.
The Balance Within, The Science Connecting Health and Emotions by Esther M. Sternberg, MD