What is it about?

Patients must agree (“consent”) to taking any medical treatments. This means that we must warn them about possible harms of the treatment. However, different ways of telling the patient about the harms can have different effects. A patient who hears, “this will feel like a bee sting” is more likely to feel pain than a patient who hears, “this will feel a bit numb”. Pain and other harms caused by expecting something bad to happen are “nocebo” (negative placebo) effects. Unlike its friendly cousin the placebo, the nocebo has been almost ignored. The result of ignoring the nocebo effect is that doctors and researchers often explain treatment risks in a way that scares patients, and actually causes harm. In this paper, Dr. Howick from the University of Oxford explains what the nocebo effect is, how to measure it properly, and how to tell patients about treatment risks in a way that is truthful and not overly scary. The paper has important implications for how consent is taken.

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Why is it important?

Because medical treatments are the bedrock of medical practice. The recent evidence about the effects of negative words ('nocebo effects') shows that we are reducing the benefits of our medical treatments with the way we communicate. This needs to change.


Communication between patients and doctors is often seen as something soft or intangible. This paper shows that the evidence linking negative words with negative outcomes is as rigorous as the evidence about the effects of drugs. The ethical implications of negative words have been all but ignored and this has to change.

Jeremy Howick
University of Oxford

Read the Original

This page is a summary of: Unethical informed consent caused by overlooking poorly measured nocebo effects, Journal of Medical Ethics, February 2020, BMJ,
DOI: 10.1136/medethics-2019-105903.
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