The International Association of the Study of Pain (IASP), amongst its many other roles is the sole arbiter of the definition of pain. It, until very recently defined pain as ‘An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage’. This definition dates back to 1979, so has been the definition of pain for my entire career. Not only did this make it easier for me to remember for exam purposes, it also gave me an opportunity to understand the key elements of this definition.
1 – Any unpleasant sensory experience, by definition, is painful. As well as pain in the classic sense, this also incorporates other sensations such as paraesthesia (pins and needles), dysaesthesia (crawling sensations) or intense itch
2 – An unpleasant emotional experience can also meet the definition of pain. The sensory and emotional aspects of pain are usually, but not always co-existent.
3- You do not have to have actual tissue damage to describe pain. While tissue damage is painful, not all painful experiences result in tissue damage. Indeed, pain can be described in tissues that do not exist – ie phantom limb.
Is This Definition of Pain Still Relevant?
In 2018, the IASP convened a 14 member, multi-national, expert panel with wide ranging experience in clinical practice and scientific research, seeking input from multiple stakeholders. The role of this panel was to ask the question ‘Does the progress of our knowledge of pain over the years warrant a re-evaluation of the definition?’
After multiple meetings over a 2 year period, this 14 member panel decided that the current definition was indeed out dated for the modern environment of chronic pain management and research, and so, after much debate, the following revised definition was put forward to the council of the IASP for consideration.
2020 revised definition of pain
‘An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.’
So does this bring the definition of pain bang up to date, ready for the rigours and demands of the 21st century?
Obviously, getting on to a prestigious 14 member international panel, and attending international meetings for 2 years is nice work if you can get it. I’m not so sure if there was anything wrong with the original definition, or if there was, whether this minor tweak addresses it. I guess they had to do something to justify the effort. Whether this has any impact on day-to-day pain management remains to be seen.