Revised definition of pain after four decades

The revision of the International Association for the Study of Pain defines pain as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”¹.

Dated from 1979, the first definition recommended by the Subcommittee on Taxonomy and adopted by the IASP Council conceptualized pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”. This definition was widely accepted by health professionals and researchers of the field and adopted by several professional organizations, governmental or not, including the World Health Organization (WHO).

Over the course of 41 years, the comprehension of the pain phenomenon went through revolutionary changes, including very important publications on its definition and classification, specially in the last decade. In the past, a dichotomous view considered pain only as nociceptive or neuropathic, which excluded other conditions, such as fibromyalgia. In 2016 a third descriptor appeared, nociplastic pain, improving the classification of other painful conditions².

In 2019 another issue of concept and classification was resolved when chronic pain was included in the International Classification of Diseases (ICD)³. This demand resulted from the joint action of IASP and WHO Task Forces. Currently, pain is included in the ICD-11 with 7 sub-categories, 1 primary and 6 secondary.

Recently, some professionals and researchers of the field of pain argued that the progress in the understanding of pain justified a reevaluation of the definition, presenting proposals of modification, strong opinions in favor or opposing to the need for a revision and, therefore, discussing modifications through the last few years^4,5. Due to the continuous and consistent advances in knowledge about pain and its mechanisms, pain terminology must also be modified and adjusted. Therefore, in 2018, IASP called for a multinational Presidential Task Force composed of14 professionals with extensive experience in pain-related clinical and/or basic science to evaluate the current definition and its explanatory notes and recommend whether such a definition should be maintained or changed.

The revision offers summary of the critical concepts, commentary analysis of the IASP members and the public, as well as the final recommendations of the committee on the definition revision and the notes that were discussed for two years. Finally, the Task Force recommended a revised definition of pain in the beginning of 2020.

The board of the Sociedade Brasileira para o Estudo da Dor (SBED - Brazilian Society for the Study of Pain) published not only the official translation into Portuguese of the revised definition and its notes, but also the entire article, considering the semantic and linguistic aspects for the Portuguese language and Brazilian context^6,7. The necessary steps for the official translation of this definition of pain and its complementary notes into Portuguese were carried out, in order to ensure that the Brazilian population had wide access to a uniform discourse in their native idiom.

Initially, the article was completely translated by a language professional specialized in Portuguese and English. Next, a review and discussion of the translation was brought forward by members of the board, clinicians and/or researchers on the field of pain with, at least, 15 years of experience. The individual reviews were shared and specifically analyzed in online real time remote meetings, followed by a second phase of review until a consensus was reached.

The definition revised in 2020, conceptualizing pain as “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”, presented an unambiguous and concise formulation, easily translatable to other languages; comprising the most varied experiences of pain, its diversity and complexity, being valid for acute pain as well as chronic pain; applicable in all conditions of pain, from humans to animals and, most importantly, defined by the perspective of the person who is in pain^1,6,7.

The definition is complemented by 6 explanatory notes that come to be a list of items that include etymology: 1. Pain is always a personal experience that is influenced, to varying degrees, by biological, psychological and social factors. 2. Pain and nociception are different phenomena. Pain cannot be determined exclusively by the activity of sensitive neurons. 3. through their life experiences, people learn the concept of pain. 4. A person’s account of an experience of pain should be respected. 5 Although pain usually plays an adaptive role, it can have adverse effects on function as well as social and psychological well-being. 6. Verbal description is only one of several behaviors that may express pain; the inability to communicate does not invalidate the possibility of a human or animal to feel pain^1,6,7.

These explanatory notes complement the definition of pain, recognizing, but not being restricted to, advances in knowledge based on the modern neuroscience of pain, also incorporating other relevant factors such as cognition, behaviors, as well as cultural and educational factors.

At the end of the explanatory notes, etymological information on the origin of the word pain is presented: 1. from Middle English, Anglo-French peine (pain, suffering), 2. from Latin poena(sentence, punishment) and 3. From the Greek poin-e (payment, penalty, reward)^1,6,7.

A definition provides comprehension, concept, or common idea about a determined word. The definition of the word generates the possibility of acknowledgment, value, signification and its objective is to direct a specific discussion on all related subjects and must only be rejected in the case of an explicit or implicit logical contradiction. This type of definition is supposed to be used for as long as it serves its work purpose, therefore it is, in essence, temporary. This revised definition of pain is timely and in line with all IASP’s current efforts to advance ontological structures of pain, and this editorial does not intent to interpret or judge this revision. All of the facts that occurred in the process executed by the Task Force were exposed in the IASP publication, as well as the narration of the reiterated discussions and interpretations made by the members and their consultants.

Instead, the IASP’s initiative should be valued by understanding the changes in the scenario of pain and welcoming the eagerness of the scientific and professional community for the need of reevaluation, as well as the effort and dedication of the Task Force members in developing a process for reviewing the definition of pain according to epistemological, ontological and practical dimensions, whose steps were conducted in a socially responsible, democratic, participatory, transparent and scientific method-based manner.

A uniform and widely known terminology in the field of pain that communicates information about patients and their pain is important to determine basic terms of pain and the classification of their syndromes and clinical conditions, which has been the constant focus of several IASP committees. Thus, the proposed definition creates a common understanding of the term “pain” for health professionals, researchers and people with pain all around the globe, also providing a base for researches in the field, with the objective of minimizing epistemological mistakes, and influencing public health politics, which tend to provide improvement in health care. As the Task Force itself recommended, this revised definition of pain published through a narrative review is a living document to be updated in line with the future progress of the field.

Yours sincerely,

Diretoria da Sociedade Brasileira para o Estudo da Dor (SBED) - Gestão 2020-2021

REFERENCES

• ¹
  Raja SN, Carr DB, Cohen M, Finnerup NB, Flor H, Gibson S, et al. The revised International Association for the Study of Pain definition of pain: concepts, challenges, and compromises. Pain. 2020;23. doi: 10.1097/j.pain.0000000000001939. Online ahead of print.
  » https://doi.org/10.1097/j.pain.0000000000001939
• ²
  Kosek E, Cohen M, Baron R, Gebhart GF, Mico JA, Rice ASC, Rief W, Slu-ka KA. Do we need a third mechanistic descriptor for chronic pain states? Pain. 2016;157(7):1382-6.
• ³
  Treede RD, Rief W, Barke A, Aziz Q, Bennett MI, Benoliel R, et al. A classification of chronic pain for ICD-11. Pain. 2015;156(6):1003-7.
• ⁴
  Williams ACC, Craig KD. Updating the definition of pain. Pain. 2016;157(11):2420-3.
• ⁵
  Cohen M, Quintner J, van Rysewyk S. Reconsidering the International Association for the Study of Pain definition of pain. Pain Rep. 20185;3(2):e634.
• ⁶
  https://sbed.org.br/wp-content/uploads/2020/08/Defini%C3%A7%C3%A3o-revi-sada-de-dor_3.pdf
  » https://sbed.org.br/wp-content/uploads/2020/08/Defini%C3%A7%C3%A3o-revi-sada-de-dor_3.pdf
• ⁷
  Jornal Dor (Publicação da Sociedade Brasileira para o Estudo da Dor - Ano XVIII - 2° Trimestre de 2020 - edição 74, 11-8.

Publication Dates

• Publication in this collection
  21 Sept 2020
• Date of issue
  Jul-Sep 2020