The IASP Classification of Chronic Pain for ICD-11: Chronic Primary Pain

Michael Nicholas; Johan W.S. Vlaeyen; Winfried Rief; Antonia Barke; Qasim Aziz; Rafael Benoliel; Milton Cohen; Stefan Evers; Maria Adele Giamberardino; Andreas Goebel; Beatrice Korwisi; Serge Perrot; Peter Svensson; Shuu-Jiun Wang; Rolf-Detlef Treede; The IASP Taskforce for the Classification of Chronic Pain


Pain. 2019;160(1):83-87. 

In This Article

The IASP Task Force ICD Initiative

To remedy the lack of accurate classification of chronic pain in general and chronic pain where disease-oriented pain diagnoses are not appropriate, the International Association for the Study of Pain (IASP) established a Task Force that worked in close co-operation with WHO representatives in generating a systematic and improved classification of chronic pain.[56] The classification is dedicated exclusively to chronic pain syndromes and excludes acute pain. The Task Force subchapter on CPP was steered by the first 2 authors.

Chronic pain was defined as pain[23] that lasts or recurs for longer than 3 months.[55] This definition was chosen because it provides a clear operationalization that is in line with widely used criteria in other fields of medicine. A code for the severity of the chronic pain syndrome was added, which records the intensity of the pain, the emotional distress, and the interference in daily activities due to pain. To assist with the specification of the severity of the pain, the use of numerical rating scales categorizing its 3 dimensions is recommended.[55] Each dimension can be rated on a 0 to 10 scale (where 0 = nil and 10 = extreme), which can then be categorized to yield a code (0-3) for each dimension (where 0 = absent; 1–3/10 = 1 or mild; 4–6/10 = 2 or moderate; and 7–10/10 = 3 or severe). This will allow a case to be given a code of 0 to 3 for each dimension. The use of these codes is illustrated in the case vignettes 1–5 accompanying the text. ICD-11 will be coordinated with the International Classification of Functioning, Disability and Health (ICF) that will provide additional features of activities and participation.[32]

The classification presented here is integrated with the "frozen version" of ICD-11, published by WHO on June 18, 2018. A previous version had undergone field testing by WHO for line coding and case coding in 2017, through the IASP website.