nocebo

nocebo — noun

1. a harmful physical or emotional reaction that occurs when a person expects a tre

1.nounC2
Definition

a harmful physical or emotional reaction that occurs when a person expects a treatment to cause problems rather than help them — the negative counterpart of the placebo effect.

Example

Hui was told the pill might cause headaches, and she soon developed a nocebo reaction.

Though the cream had no active ingredients, Élise's nocebo response made her skin feel irritated.

nocebo response triggered by an inactive substance

Common collocations
  • experience a nocebo response
  • trigger a nocebo effect
  • develop a nocebo reaction
  • classic nocebo effect
  • textbook nocebo effect
  • genuine nocebo response
Synonyms
  • negative placebo effect

    more descriptive but less concise; used mainly in introductory or explanatory writing

  • nocebo effect

    the full form of the term; interchangeable in most contexts and preferred in formal academic writing

  • expectation-induced symptom

    broader in scope — covers symptoms from any expectation, not only treatment-related ones

Antonyms
  • placebo effect

    the opposite phenomenon: improvement in symptoms caused by positive expectations about a treatment

Grammar Patterns

the nocebo effect

nocebo response

nocebo reaction

Usage Note

Frequently discussed in medical contexts involving informed consent and communication of side effects. The nocebo effect is the negative counterpart of the placebo effect — it describes harm caused by negative expectations rather than by the treatment itself.

Common Mistakes

The nocebo effect is when a patient gets worse.
The nocebo effect is a harmful reaction caused by negative expectations about a treatment.
'is when' is vague; define the phenomenon directly.
I had a nocebo yesterday.
I experienced the nocebo effect after reading the list of possible side effects.
'nocebo' alone is not idiomatic for a personal experience; the full term 'nocebo effect' or 'nocebo response' is standard.

Word family

  • nocebo effect
    noun phraseC2

Synonym discussion

Sense: noun/1

'Nocebo' and 'nocebo effect' are used interchangeably in medical writing, though 'nocebo effect' is preferred in formal academic contexts and is more recognisable to readers. 'Negative placebo effect' is a transparent descriptive alternative used mainly in explanatory material for lay audiences. The 'placebo effect' is the opposite phenomenon — symptom improvement from positive expectations. Both are psychogenic responses originating in the mind rather than in the chemistry of the treatment itself. For example, a patient may develop a nocebo headache from a sugar pill after being warned about side effects, whereas the same pill could produce a placebo pain-relief effect if the patient believed it was an active drug.

nocebo ↗nocebo effectnegative placebo effectplacebo effect

Common collocations

Nouns

  • nocebo effect
  • nocebo response
  • nocebo reaction

Phrases

  • the nocebo phenomenon
  • nocebo-related symptoms

Etymology

LatinEnglish

Coined in the 1960s by medical researcher Walter Kennedy as the negative counterpart of 'placebo' (Latin for 'I will please'). 'Nocebo' comes from the Latin verb 'nocēre' (to harm), taking the future-tense form 'nocēbō' meaning 'I will harm'. The term was created to describe situations where a patient's negative expectations, rather than the treatment itself, produce harmful effects.