Central Sensitization: Explanation or Phenomenon?

Abstract

Central sensitization (CS) is a popular concept that is frequently used to explain pain hypersensitivity in a large number of pain conditions. However, the concept of CS is now also increasingly used to explain nonpain symptoms. In the present commentary, we argue that CS, as defined by the International Association for the Study of Pain, refers to changes in nociceptive neurons only and therefore cannot be applied to enhanced responses to stimuli other than nociceptive and/or pain. Moreover, the evidence for CS in widespread pain (other than secondary hyperalgesia) and many other conditions is scarce to absent. As a consequence, CS is a descriptive label for the explanandum rather than an explanation and, as such, suffers the risk of being a circular explanation. Finally, cognitive and emotional factors should also be considered as potential mechanisms for the wide range of phenomena that are currently interpreted as evidence for CS.