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

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 3 adult patients with WS. METHODS:This report describes the clinical presentation and long-term follow-up of 3 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 3 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.