Placebo, nocebo and care effect by Mathilde Alice Krähenbühl. Placebo, nocebo and care responses are an interesting challenge of eastern medicine. From their definitions and the problems arising through them, to their usage in randomized controlled trials, they fascinate and confuse. However, when demystified and properly defined, they represent a very good model for the understanding of the role of context within treatment and can be used to the advantage of modern science. The placebo, nocebo and care effect have biological and neurophysiological consequences that are at the basis of our understanding of cures, diseases, and the art of medicine. Learning how to maximize the placebo and care effects as well as minimize the nocebo effect, understanding which major conditions are concerned and changing our perceptions concerning them are some of the possible applications of bettering our understanding of this mysterious-sounding subject.
The present article is based on a survey of literature, among which about a hundred key publications, enlighting different aspects related to the placebo question, are being reviewed. It starts with history and how the placebo concept gradually emerged as a well-founded and important component of the art of medicine (section IV). During the last century, a typology of the placebo effects gradually emerged, and different aspects were identified, such as the effects of deception, conditioning and suggestion (section V). Also, two distinct placebo mechanisms (bottom up and top down) were identified. In section VI, some of the major scientific contributions concerning the relation between placebo / nocebo and neurological changes are being reviewed. The responders to placebo are numerous. In section VII, main responders are mentioned. They include personality and genetics, for which present state of the art knowledge is presented. Trying to maximize the placebo effect is an important concern. In section VIII, various influence parameters are listed and commented in reference to corresponding research studies, including the care effect and doctor-patient interaction, as well as the influence of a multiplicity of factors such as medication labelling and pricing, frequency of administration, type of treatment (oral vs subcutaneous, physical vs oral), and belief of the subject concerning the treatment. Finally, to understand and quantify the placebo effects it is necessary to relate them to the notion of pain. The state of the art concerning that question is being presented in section IX, in which the efficacy of placebo for the treatment of depression and anxiety is being discussed on the basis of state of the art knowledge.