Clinical Characterization of Juvenile Fibromyalgia in a Multi-Center Cohort of Adolescents Enrolled in the FIT Teens Trial

Juvenile Fibromyalgia (JFM) is a complex chronic pain condition that remains poorly understood. The study aimed to expand the clinical characterization of JFM in a large representative sample of adolescents with JFM and identify psychological factors that predict pain interference.Participants were 203 adolescents (12-17 years) who completed baseline assessments for the multi-site Fibromyalgia Integrative Training for Teens (FIT Teens) randomized control trial. Participants completed the Pain and Symptom Assessment Tool (PSAT), which includes a Widespread Pain Index (WPI, 0-18 pain locations) and Symptom Severity checklist of associated somatic symptoms (SS; 0-12) based on the 2010 ACR criteria for Fibromyalgia. Participants also completed self-report measures of pain intensity, functional impairment, and psychological functioning.Participants endorsed a median of 11 painful body sites (WPI) and had a median SS score of 9. Fatigue and nonrestorative sleep were prominent features and rated as moderate to severe by 85% of participants. Additionally, neurologic, autonomic, gastroenterological, and psychological symptoms were frequently endorsed. WPI was significantly correlated with pain intensity and catastrophizing, while SS scores were associated with pain intensity and all domains of physical and psychological functioning. Depressive symptoms, fatigue, and pain catastrophizing predicted severity of pain impairment.JFM is characterized by chronic widespread pain with fatigue, nonrestorative sleep, and other somatic symptoms. However, how diffusely pain is distributed appears less important to clinical outcomes and impairment than other somatic and psychological factors highlighting the need for a broader approach to the assessment and treatment of JFM.