Comment on "Cost-Saving Early Diagnosis of Functional Pain in Nonmalignant Pain: A Noninferiority Study of Diagnostic Accuracy".

Dr. Cámara et al. published a diagnostic testing that distinguishes functional pain from neuropathic and nociceptive pain [1]. It is very important to distinguish between neuropathic pain and nociceptive pain, because treatment of the two kinds of pain is completely different. However, distinction between neuropathic pain and functional pain provides little clinical value, because treatment of the two kinds of pain is almost the same. Functional pain corresponds to central sensitivity syndromes such as fibromyalgia (FM) and its incomplete forms. To my knowledge, if FM is neuropathic pain, FM is the disorder that has the highest number of science-based treatments among neuropathic pain. Effective treatment for FM is effective for other neuropathic pain. From the viewpoint of treatment, we do not have to distinguish neuropathic pain from functional pain. Continuance of any kinds of pain causes central sensitization in the brain and/or spinal cord, and central sensitization itself causes pain. I believe that pain due to central sensitization is central neuropathic pain and functional pain is central neuropathic pain. FM has a feature of central neuropathic pain. I believe that we do not have to distinguish neuropathic pain from functional pain.