Nocebo phenomena: 'Negative non-specific effects'
Authors: Greville-Harris, M. and Dieppe, P.
The placebo response (improvement in disease or illness in responseto an intervention with no active ingredient) is a well-recognisedphenomenon, particularly in the context of clinical trials. Its opposite(worsening in response to an 'inactive' intervention) is less welldocumented and understood, in part because of the difficultiesencountered in studying it. However, there is now a considerableliterature reporting nocebo responses in trials, in response to medicationprescriptions, as well as in response to population-based activities such asthe introduction of mobile phones. In addition, and given emphasis in thisarticle, a well-intentioned health care consultation can result in negativeoutcomes.Our research has investigated the role of invalidation, and of feelingunsafe or threatened, on the induction of a nocebo response. Our workhas led us to believe that it is easier to induce a negative response than apositive one within healthcare consultations, and that nocebo is morepowerful than placebo ('bad is more powerful than good').We conclude with a brief discussion of the ethical and clinicalimplications of the nocebo response