Updating the definition of pain Amanda C de C Williams University College London and Kenneth D Craig University of British Columbia

Strengths: Applies to acute and chronic pain IASP definition of pain: An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage (1979). Strengths: Applies to acute and chronic pain Emphasises subjective experience Does not require evidence of tissue damage or pathology Gives weight to sensory and emotional aspects Applicable in scientific and clinical settings

Problems: Clinical pain is almost always more than “unpleasant” IASP definition of pain: An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Problems: Clinical pain is almost always more than “unpleasant” Refers only to sensory and emotional qualities, neglecting important features The final phrase, “or described in terms of such damage” is ambiguous

Problems: Pain is a distressing experience Clinical pain is almost always more than “unpleasant” The final phrase, “or described in terms of such damage” is ambiguous Refers only to sensory and emotional qualities, neglecting important features [Pain is] An unpleasant sensory and emotional experience Pain is a distressing experience associated with actual or potential tissue damage, or described in terms of such damage. with sensory, emotional, cognitive and social components.

Pain is a distressing experience associated with actual or potential tissue damage, with sensory, emotional, cognitive and social components. Improvements: Adds cognitive and social components seen in human and nonhuman animals Cognitive neuroscience highlights attention, memory, appraisal, descending modulation Personal narratives highlight social contexts: family, work, participation Removes unnecessary reference to self-report in use of the word “describes”

We would also revise the Note that qualifies the definition: We would shorten it, and remove inconsistencies As before, the Note specifies assessment methods for different circumstances and needs Conclusion Pain science and practice need an improved definition. We hope to contribute to this through active discussion and debate of our proposal.