心因性疼痛を考える：用語としての認知性疼痛の提案

抄録

Chronic pain is one of the common health problems among the general population. Various mechanisms are involved in the pathophysiology of pain, and a correct understanding of its pathophysiology or cause is important for an optimal management of pain. In terms of the physiological anatomy, pain with physical ⁄ organic causes can be classified mainly as “nociceptive pain” or “neuropathic pain.” However, there is also pain that does not fall into either of these two categories. This type of pain is often considered as a third classification, but its definition has not been standardized globally. In Japan, this type of pain is often called “psychogenic pain,” even when the pain is not attributed to psychological factors. However, it may not be an appropriate term for this particular type of pain. Firstly, because there is no standardized definition, physicians differ in how they classify pain as “psychogenic.” Additionally, the term “psychogenic” could give negative impressions to patients, which can deteriorate the patient–physician relationship and may result in poor treatment outcomes. In this paper, we have discussed these problems and proposed a new term “cognitively perceived pain” for this third category of pain, with the aim to foster a more appropriate, and easy–to–understand classification of pain. “Cognitively perceived pain” encompasses all pain that is neither nociceptive nor neuropathic pain, including that described as centralized pain or sensory hypersensitivity, in addition to psychogenic pain according to its original meaning (i.e. pain attributable to psychological factors). Because pain is perceived in the brain, the presence of any pain implies the impairment or abnormality of cognition. The proposed term is straightforward to convey the essence of pain without including any negative–sounding words. We hope that this term and its concept will be widely accepted, and help to increase understanding of this poorly defined category of pain.