Functional Neurological Symptom Disorder in Williams Syndrome: Case series and Review of Relevant Literature.

Abstract Background Williams syndrome (WS) is a neurodevelopmental disorder associated with several medical and psychiatric comorbidities. Objective: To describe the clinical presentation and treatment course of functional neurological symptom disorder (FNSD) in three adult patients with WS. Methods This report describes the clinical presentation and long-term follow-up of three individuals with WS and FNSD who experienced a range of clinical presentations and responses to treatment. The literature on the clinical assessment and treatment of FNSD as it applies to patients with neurodevelopmental disorders is reviewed. Results FNSD treatment strategies used in the general population were successfully adapted for these three patients. Literature on the diagnosis and treatment of FNSD in patients with neurodevelopmental disorders is lacking. Conclusions FNSD may be more common in individuals with WS than previously appreciated and future studies describing the prevalence, clinical presentation, risk factors, and treatment of FNSD in WS are needed.