Definition of pain updated for the first time since 1979

27 July 2020

After 40 years, the globally accepted definition of pain originally developed by the International Association for the Study of Pain (IASP) in 1979, has been revised and updated to reflect advances in our understanding of pain.

The resulting new definition will have far-reaching impact on the world of pain management. The IASP’s full report on how the new definition came to be adopted can be downloaded here. For ease of access, we reproduce below the new definition and its six key notes:

Revised IASP definition of pain (2020):


An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.


  • Pain is always a personal experience that is influenced to varyingdegrees by biological, psychological, and social factors.
  • Pain and nociception are different phenomena. Pain cannot be inferredsolely from activity in sensory neurons.
  • Through their life experiences, individuals learn the concept of pain.
  • A person’s report of an experience as pain should be respected.*
  • Although pain usually serves an adaptive role, it may have adverseeffects on function and social and psychological well-being.
  • Verbal description is only one of several behaviors to express pain;inability to communicate does not negate the possibility that a human ora nonhuman animal experiences pain.


Middle English, from Anglo-French peine (pain, suffering), from Latin poena (penalty, punishment), in turn from Greek poine (payment, penalty, recompense).

* The Declaration of Montreal, a document developed during the First International Pain Summit on September 3, 2010, states that “Access to pain management is a fundamental human right.”

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