Skip to content
Know.itKnow.it
Create an animated lesson
On request

This article is free to read. Creating a lesson uses your daily or stored credits; review the language and settings before starting.

What is the nocebo effect?

PsychologyLesson on requestFree to read

Quick answer

The nocebo effect is the placebo effect's negative twin: when negative expectations cause real, harmful symptoms. If you expect a treatment to cause side effects, you may genuinely feel them — even from a harmless sugar pill. Negative expectations can produce real symptoms.

Key things to understand

  1. Negative expectations can produce real symptoms.
  2. It's the opposite of the placebo effect.
  3. Even harmless substances can trigger side effects.
  4. It shows how powerfully the mind affects the body.

People also ask

What is the nocebo effect?
When negative expectations cause real, harmful symptoms, even from a harmless or inactive treatment.
How is nocebo different from placebo?
Placebo brings benefit from positive expectation; nocebo brings harm from negative expectation.
Why does the nocebo effect matter in medicine?
Warning patients of side effects can sometimes cause those very symptoms through expectation.