The new medical model: a renewed challenge for biomedicine.

CMAJ | MAY 1, 2017 | VOLUME 189 | ISSUE 17 © 2017 Joule Inc. or its licensors O ver the past 25 years, several new “medicines” have come screeching onto health care’s various platforms, including narrative medicine, personalized medicine, precision medicine and person-centred medicine. Philosopher Miriam Solomon calls the first three of these movements different “ways of knowing” or “methods,” and argues that they are each a response to shortcomings of methods that came before them.1 They should also be understood as reactions to the current dominant model of medicine. In this article, I will describe our dominant model, which I call “the new medical model.”2 I will argue that several towering problems in modern medicine can be traced to its philosophical foundations, which calls for philosophical analysis. Forty years ago in his article “The Need for a New Medical Model: A Challenge for Biomedicine,”3 psychiatrist Dr. George Engel wrote: “The dominant model of disease today is biomedical.” Engel argued that the “biomedical model” or “biomedicine” was the traditional model of disease as well as the orthodox model of medical practice. This model conceptualized disease as deviation from normal biological functioning owing to biological determinants, described in the language of the basic biomedical sciences, including anatomy, physiology and molecular biology. The biomedical model directed the physician to correct disease and restore normal functioning. How so? By using knowledge from these very sciences. Because of the perceived “reductionism” and neglect of the psychological and the social among the components of the model, the biomedical model has since been a target of incisive criticisms, many of which have been advanced by scholars in the humanities and social sciences, including philosophers.4 Although biomedicine is sometimes called “the medical model,” I will refer to it as the “old medical model” for reasons I will explain shortly. We can identify at least three essential components of the old medical model as described by Engel: a disease concept, an ethic and a logic. Its disease concept is disease-as-bodily-biological-dysfunction. Its ethic or ethical imperative is to cure the disease, fix the dysfunction. Finally, its logic or “style of scientific reasoning”5 consists of biomedical “mechanistic reasoning,” reasoning through biomedical mechanisms of health and disease. In summary, the kind of medicine modelled by the old medical model is one in which physicians cure biological disease using biomedical mechanistic reasoning. The paradigmatic diseases for the old model are acute infectious diseases, which are generally curable, and can be understood and treated using biologic rationale: for a bacterial infection, treat with an antibiotic to halt the germ’s growth or survival, and thus clear the infection. By the time Engel wrote his “challenge to biomedicine,” health care was already being transformed by two major developments: the rise of chronic diseases and evidencebased medicine. Chronic diseases defy the old medical model because they are generally incurable, and many patients with chronic disease have not one disease but multiple distinct diseases (multimorbidity). Meanwhile, evidence-based medicine defies the old model by privileging reasoning from the results of clinical epidemiologic studies rather than mechanistic reasoning. In response to these new clinical realities, the old medical model has evolved into the “new medical model,” which represents the cure, prevention and management of biological disease(s) using the reasoning and principles of evidence-based HUMANITIES | MEDICINE AND SOCIETY