Wetenschapsforum

Een placebo (Latijn en het betekent: 'ik zal behagen') is een als geneesmiddel voorgeschreven of aangeprezen middel dat geen werkzame bestanddelen bevat.

Het woord placebo wordt ook gebruikt als kort voor het placebo-effect. Een placebo slaat in die betekenis op een positief psychisch effect dat optreedt door vertrouwen in de heilzame werking van een behandeling (bijvoorbeeld meer gevoel van welbehagen of opluchting). Het placebo zelf geneest echter niets en het effect ervan is kortstondig. Ook bij geneesmiddelen treedt placebo op door het verwachtingspatroon dat de patiënt heeft. Echte geneesmiddelen dienen daarom het placebo-effect significant te overstijgen om over "medicinale werkzaamheid" te kunnen spreken.

... De patient voelt zich beter als de behandelend arts meer tijd uittrekt en meer aandacht schenkt aan de patien. Door de werkdruk waar artsen tegenwoordig mee te maken hebben kunnen ze dit helaas lang niet altijd genoeg bieden.

Of vervolgens het geneeskundige effect van meer aandacht belangrijker is dan de tijd die men er extra aan kwijt is zal afhankelijk zijn van het kwantitatieve effect. Dit lijkt me zeer lastig te kwantificeren, mijn gut-feeling zegt me dat het effect van de empathische arts niet dusdanig groot is dat het een reden zou zijn om meer tijd per patient vrij te maken.

...25 years later I began advising undergraduates at Stanford University, many of whom had come to Stanford with the hope of eventually becoming a physician. From many of these students I heard what would become a mantra. "I used to be pre-med, but…" It seemed common knowledge among these students that a C+ in organic chemistry was simply incompatible with hopes of becoming a physician. If you can't do science, you can't succeed as a physician. If all you can pull is a C+ in chemistry, it's unlikely you'll get into medical school. By then I had more than two decades of clinical practice experience to teach me what a great physician was. A great physician creates a bond of communication and trust with his or her patient; a great physician can sense the feelings the patient is struggling to express or afraid to try; a great physician is also technically competent and conversant in medical science. ...


I went back in the literature of medical education 40 years before the time of Vaughan's comments, and found no scientific evidence to support his assertion. I went ahead, through more than 90 years of published research. I did find evidence that performance in the undergraduate sciences can predict failure in the initial sciences courses in the medical school curriculum. Those who score in the bottom 10—20% on standardised tests of scientific knowledge are the most likely to fail the early years of medical school (although more than half would succeed, given the chance). ...



It found consistent evidence that performance in the premedical sciences is inversely associated with many of the personal, non-cognitive qualities so central to the art of medicine. I first found this evidence in my own educational back yard. ...


Harrison Gough, a psychologist at the University of California, Berkeley, administered a series of psychological tests to 1071 students entering medical school at UCSF between 1955 and 1967. Gough reported that students' undergraduate science grades and MCAT science scores were associated with grades in the first 2 years of medical school, but were, "almost completely unrelated to performance in the fourth year and to faculty rating of general and clinical competence". He then compared the psychological profiles of these students with their performance in premedical sciences. He found that the students who did better in science were, "narrower in interests, less adaptable, less articulate, and less comfortable in interpersonal relationships". ...


A number of others have found the psychological profile of students who perform best in the premedical sciences to be the reverse of what one might hope for in a physician. Writing in the 1970s, Witkin found students who were most successful in the sciences, "have an impersonal orientation: they are not very interested in others". Tutton's studies of medical students in Australia in the 1990s found that students who did the best in the premedical sciences scored lower on standardised measures of empathy and tended to be "shy", "submissive", "withdrawn", or "awkward and ill at ease socially", characteristics the author suggested are, "the antithesis of what most of us would want in a clinician". ...



The scientific evidence in support of this conclusion is convincing. I do not mean to suggest that knowledge of science is irrelevant to medical education and medical practice. There is a critically important threshold of scientific knowledge that forms the foundation on which a medical education is built. However, once one has exceeded this cognitive threshold, additional scientific knowledge adds little to subsequent performance as a physician. ...


If what we seek from our students is professional excellence, we must be careful to base the manner in which we select these students on scientific evidence, not on superstition. Beyond its religious connotation, The Oxford English Dictionary suggests that superstition represents an, "irrational or unfounded belief". The belief that one's knowledge of science represents a continuous metric of the quality of one's preparation for the study of medicine represents precisely such an "unfounded belief". There seems to be no scientific evidence to support it. Great physicians base their professional practice on a threshold of scientific knowledge they have acquired throughout their career. Upon this foundation they build an artistic display of communication, compassion, empathy, and judgment. In selecting students for the study of medicine, we must be careful to avoid superstition, and to adhere to the evidence that equates as metrics of quality a preparation in fundamental scientific principles and the non-cognitive characteristics that are conducive to professional greatness.