RT Journal Article SR Electronic T1 Unethical informed consent caused by overlooking poorly measured nocebo effects JF Journal of Medical Ethics JO J Med Ethics FD BMJ Publishing Group Ltd and Institute of Medical Ethics SP 590 OP 594 DO 10.1136/medethics-2019-105903 VO 47 IS 9 A1 Jeremy Howick YR 2021 UL http://jme.bmj.com/content/47/9/590.abstract AB Unlike its friendly cousin the placebo effect, the nocebo effect (the effect of expecting a negative outcome) has been almost ignored. Epistemic and ethical confusions related to its existence have gone all but unnoticed. Contrary to what is often asserted, adverse events following from taking placebo interventions are not necessarily nocebo effects; they could have arisen due to natural history. Meanwhile, ethical informed consent (in clinical trials and clinical practice) has centred almost exclusively on the need to inform patients about intervention risks with patients to preserve their autonomy. Researchers have failed to consider the harm caused by the way in which the information is conveyed. In this paper, I argue that the magnitude of nocebo effects must be measured using control groups consisting of untreated patients. And, because the nocebo effect can produce harm, the principle of non-maleficence must be taken into account alongside autonomy when obtaining (ethical) informed consent and communicating intervention risks with patients.There are no data in this work.