In my first and second KevinMD posts, I emphasized how medicine had failed clinicians by not training them in mental health care. All agree, it’s not our fault. Now let’s look at how successfully our teachers did prepare us for patients with medical disorders. There’s an interesting history behind how we developed expertise in physical diseases: Medicine needed to overthrow the four humors theory that guided clinical care from the time of Hippocrates in the fifth century B.C. until the 20th century.
The four humors theory
The four humors theory posited that an imbalance of four circulating humors (black bile, yellow bile, blood, phlegm) represented disease and caused symptoms, disability, and even death; for example, an imbalance of black bile leading to depression (melancholia). Physicians restored balance of the four humors by bloodletting, sometimes exsanguinating the unfortunate patient. It would not be until the early 1900s that clinicians finally abandoned the four humors and bloodletting. It will perhaps surprise you to learn that Sir William Osler’s 1912 textbook advised: Pneumonia is one of the diseases in which a timely venesection may save life … the abstraction of from 20 to 30 ounces of blood is in every way beneficial.
Let’s see how this old theory was gradually eased out.
Mind-body split theory
With virtually no medical advances since Hippocrates, 16th-century physicians, led by Andreas Vesalius, clamored for human dissection to better inform teaching, human anatomy then the basic science of medicine. Long rejected by the Church as blasphemous, Pope Clement finally relented in 1537 and allowed human dissections for teaching. But he had one restriction that launched the splitting of the mind away from the body: Doctors could only dissect the body from the neck down; the head, as the site of the mind, body, and soul, remained the Church’s province. The theory’s isolated focus on the physical body in anatomy then spread with a similar focus into the other newly evolving disciplines such as chemistry and physiology.
In the next century, René Descartes firmly established the mind-body split theory. His powerful influence ensured that medicine would restrict itself to physical disorders and not address mind and other personal issues. The duality would not begin in clinical care, however, until the 18th century with a discovery that refuted the idea that an imbalance of the four humors was a disease. Doctors, led by Giovanni Battista Morgagni, had begun closely studying autopsy findings and concluded that the abnormal organs they observed were the underlying disease and that they caused physical symptoms, disability, and death. This observation represented the origin of modern medicine’s guiding principle for physical diseases: clinical-pathological correlation (CPC). As a result, in a trend that continues today, 18th-century physicians began ignoring patients’ personal, emotional, and social issues to focus on the physical symptoms that would lead to a disease diagnosis.
Modern scientific medicine
Two issues in the 20th century led finally to complete implementation of the mind-body split (and its CPC) and today’s successes. First, the Flexner Report of 1910 established the primacy of the duality by requiring that medical schools intensively teach CPC and stop teaching the four humors and bloodletting. Second, the subsequent discovery of effective treatments, such as sulfas, penicillin, and ether, led to advances early in the last century. They were followed throughout the century by a progressive explosion of successful treatments (control of epidemics [polio, smallpox, measles], beta blockers, coronary care units, statins, heart and kidney transplants, drugs to cure AIDS and some cancers, and most recent, GLP-1 agonists) and technological advances (surgical techniques, magnetic resonance imaging, the genome). For the first time since the beginning of medicine in the fifth century B.C., something happened that had never occurred. Medical treatments benefited patients. And by a lot. Life survival increased from 40 years in 1900 to nearly 80 years in 2000. The mind-body split succeeded in spades.
We can feel proud to be the heirs of such resounding success and privileged to have been taught to deploy it. While we have work to do in mental health and prevention, our vast success in physical diseases suggests our capacity to morph our expertise into care that integrates the psychological and social dimensions of patients with their diseases.
Robert C. Smith is an internal medicine physician and author of Has Medicine Lost Its Mind?: Why Our Mental Health System Is Failing Us and What Should Be Done to Cure It.
