Adieu to an aphorism: why nociception is necessary for pain.

Abstract

An aphorism is a short saying intended to express a general truth. In this article, the popular aphorism, 'nociception is neither necessary nor sufficient for pain', is critically examined. While the latter part of that aphorism, that nociception is not always associated with pain, is not controversial, the former part, that pain can occur without nociception, poses a major challenge to scientific and clinical understanding. This article traces the origins of this part of the aphorism in the pain-related literature and the empirical evidence upon which it is based. The assertion that nociception is not necessary for pain is found to contradict the definition of pain itself. Furthermore, the observational and experimental evidence drawn upon to support that assertion does not withstand critical examination. It is shown that the assertion that nociception is not necessary for pain is untenable on both logical and biological grounds. It is argued therefore that the aphorism should be discarded in favour of 'nociception is necessary but not sufficient for pain'. The conceptual, scientific and clinical implications of this signal change in principle are discussed.