The ’nocebo’ effect: how informed consent can cause unnecessary harm in trials

Research published today in the  Journal of Medical Ethics  found that the way informed consent is currently taken causes unnecessary 'nocebo' harms. The requirement of informed consent means that it is an ethical requirement to warn patients about risks of taking part in clinical trials. But recent research shows that the way in which patients are told about these risks can actually cause harm. Dr Jeremy Howick, Director of the Oxford Empathy Programme, Faculty of Philosophy, and study author, says: 'Sometimes when we warn patients about negative side effects in a scary way it actually causes the negative side effect - a "nocebo effect".' A mega-study cited in the paper found that half of the 250,000 patients who took placebo pills (like sugar pills) in clinical trials reported some negative side effects (like pain or nausea but also more serious things). Current requirements for taking informed consent force ethics committees to focus on talking a lot about trial harms. This is understandable from a medico-legal perspective. Researchers are concerned about 'outlier' cases where a patient might say that they were not sufficiently well informed about a potential harm which they experienced.