Symptom Duration and Treatment Timing as Prognostic Factors in Pediatric Functional Motor Disorders

Background: Functional Motor Disorders (FMDs) are increasingly recognized in pediatrics, yet prognostic indicators remain poorly characterized. We examined clinical and health-care variables associated with one-year clinical outcomes. Methods: This retrospective study included 72 patients aged 9-18 years diagnosed with FMD at two tertiary pediatric hospitals in Italy and the Czech Republic between 2019 and 2023, with at least 6 months of follow-up and two valid Simplified Functional Movement Disorders Rating Scale assessments. Demographic and clinical features, referral history, therapy type and timing, and Simplified Functional Movement Disorders Rating Scale scores were analyzed at baseline, 6, and 12 months. Results: Overall, 69.4% were female, and mean symptom-onset age was 13.5 ± 1.99 years. Motor severity improved from baseline (10.25) to 12 months (3.55; P < 0.001), with 43.1% achieving remission. Longer symptom duration was independently associated with higher severity at baseline (β = 1.19, P = 0.021), 6 months (β = 2.07, P < 0.001), and 12 months (β = 1.79, P < 0.001). More prior referrals independently predicted higher 12-month severity (β = 1.00, P = 0.047). Longer time to FMD-directed treatment was associated with higher follow-up severity and a different symptom trajectory (Time × treatment timing: P = 0.007). Trajectories did not consistently differ by sex or symptom phenotype. Conclusions: Longer symptom duration, more previous referrals, and delayed treatment were associated with greater one-year motor severity. These findings underscore the prognostic relevance of symptom duration and the potential importance of timely access to care, although prospective studies are needed to establish causality.