Functional Disease
The word function has been in English usage for some 400 years. Earlier in medical terms it meant both the physiological activity of an organ and the psychological activity of the brain.
This dual usage persisted into the 1830s, after which neurologists began classifying diseases as organic and functional, the latter reserved for conditions in which current technology could not demonstrate structural alterations (Trimble 1982).Later in the century the concept of functional disease spread to medicine generally. Between 1867 and 1869 AdolfKussmaul introduced a tube into the stomach to relieve gastric dilation. He realized that, in addition to relieving the patient’s symptoms, the technique could be used to study the function of the stomach as well. The idea was picked up by Ottomar Rosen- bach, who used the term ventricular insufficiency to indicate a disproportion between the muscular reserve of the stomach and the physiological demands on it. From this grew a vast range of tests designed to determine the functional capacity of a bodily structure in health and disease. The model forms the basis of much of clinical laboratory medicine today. But once again semantic confusion entered the scene as evidence that psychological activity as well as structural changes could produce profound disturbances in bodily function.
After the work of Sigmund Freud, the word functional returned largely to its psychological meaning, and today is used indiscriminately to mean disturbed function of the nervous system, or as a word for symptoms that do not fit prevailing diagnostic terms, as well as a euphemism for a variety of psychiatric disorders and the antithesis of what is meant by organic disease. When used without qualification, it can only lead to confusion. As was said of the sobriquet psychogenic, “it would be well... to give it decent burial, along with some of the fruitless controversies whose fire it has stoked” (Lewis 1972).