PsychologyJuly 14, 2026
nocebo
/noʊˈsiːboʊ/
Definition
A phenomenon where a patient's negative expectations or suggestions about a treatment lead to a worsening of symptoms or the experience of adverse side effects.
Etymology
Derived from the Latin word 'nocebo', meaning 'I shall harm', which is the first-person singular future indicative of 'nocere' (to harm). It was coined as an antonym to 'placebo', which is Latin for 'I shall please'.
In the news
The article uses the term to contrast with the placebo effect, highlighting how negative beliefs and expectations can actively influence physiological and psychological health outcomes during medical treatment.
Placebo Effects & the Science of Suggestion (Big Questions in Psychology, Psychiatry & Neuroscience)
Read the full article ↗King's College London