Papers of the Week

The construct of “nociplastic pain” has met with divergent receptions. On the one hand it has been enthusiastically embraced, to the extent of conflation with central sensitisation of nociception and the ICD-11 entity of “primary” pain, and the promulgation of “nociplastic pain syndromes”. On the other hand, it has been rejected by those whose scepticism derives from the absence, by definition, of underlying activation of nociceptors. This article seeks to dissect these divergent views and search for reconciliation between them. One line of argument is that “nociplastic” pain, “primary” pain and “central sensitisation of nociception” reflect different domains of enquiry and should not be conflated. “Nociplastic” pain emerges as an hypothesis that confers clinical legitimacy and utility; while that hypothesis needs a minor but important modification and continues to require testing, discipline in its usage is necessary. The other line of argument discovers an unexpected impasse: the construct of “nociplastic pain” describes a phenomenon that accords with the IASP definition of pain but occurs in the absence of nociception-as-currently-defined, thus challenging the definitional link between pain and tissue damage. The article offers a resolution of this impasse, by suggesting that nociception-as-currently-defined be replaced by the resurrected concept of a nociceptive apparatus, activation of which is necessary but not sufficient for the experience of pain. One consequence would be to allow the assertions underpinning “nociplastic” to be tested empirically; another would be to relate the phenomenon of pain to a more biologically plausible basis than “actual” or “resemblance to” tissue damage. PERSPECTIVE: This article explores the major challenges posed by “nociplastic pain” to nosology and to nociception. While discipline in clinical use of the construct is required, it also emerges that the main issue is the IASP definition of nociception. A reconceptualisation of nociception is proposed, for logical, biological and clinical coherence.