Fibromyalgia: A Multifactorial Pain Disorder.

Fibromyalgia represents a complex chronic pain condition in which patients experience widespread pain accompanied by fatigue and a broad range of physical and psychological symptoms. Diagnosis relies on symptom-based diagnostic criteria that lack objectivity, making it difficult to properly diagnose and treat. The etiology of fibromyalgia is thought to be multifactorial, including neurobiological, psychological, environmental, and genetic factors. In addition to pain, many patients experience central nervous system-related symptoms, such as fatigue, sleep disturbances, cognitive impairment, anxiety, and depression. Fibromyalgia has recently been recognized as a nociplastic pain disorder. Alterations in sensory processing and pain thresholds in the central nervous system may result in the perception of widespread pain throughout the body. In a recent study, we divided fibromyalgia patients who reported widespread pain into two subgroups based on their pain threshold: a low pain threshold group and a normal pain threshold group. We comparably analyzed these subgroups by using resting-state functional magnetic resonance imaging. This hypothesis article provides an overview of the pathogenesis of fibromyalgia and discusses these two subgroups of nociplastic pain. Recognizing the various pathophysiologies of fibromyalgia will allow us to better understand patients' conditions and select appropriate treatment options for each patient.