High Prevalence and Clinical Impact of Fibromyalgia in Functional Motor Disorder

Background: Fibromyalgia is characterized by widespread pain, fatigue, sleep and cognitive symptoms. It overlaps clinically with functional motor disorder (FMD), yet its prevalence and impact in FMD remain uncertain. Objective: To determine the prevalence of fibromyalgia in FMD using the current criteria and evaluate its effects on motor symptoms and health-related quality of life (HRQoL). Methods: A total of 138 consecutive FMD patients completed the Fibromyalgia Survey Questionnaire, subjective motor ratings and HRQoL measures. Motor impairment was assessed using the Simplified FMD Rating Scale, and physical/psychiatric comorbidities and medication use were recorded. Results: Fibromyalgia was present in 44.9% of patients (95% CI: 36.5-53.6%). Those with fibromyalgia had more severe motor symptoms, lower HRQoL and greater medication use. Higher fibromyalgia severity, S-FMDRS, and psychiatric comorbidity were independent predictors of lower HRQoL. Conclusions: Fibromyalgia is common in FMD and associated with worse clinical outcomes, supporting systematic screening and integrated management.