Tourette syndrome with functional overlay: A case series

Functional tics have long been described as part of the much wider spectrum of functional neurological disorders with motor manifestations. Reports of functional tics have been relatively rare, until their recent increase on a global scale during the COVID-19 pandemic. Such reports have often been characterized by an acute or subacute onset of complex motor and vocal manifestations. Moreover, functional tics have predominantly been reported in adolescent females, whereas neurodevelopmental tics, such as those reported by patients with Tourette syndrome (TS), typically begin in younger boys. In addition to their marked severity and complexity, functional tics can merge into other types of functional neurological disorders. However, functional tics can also coexist with neurodevelopmental tics, as patients diagnosed with TS can present with a functional overlay (dual diagnosis). In the present study, we report the clinical characteristics of a case series of 10 patients diagnosed with both TS and functional tics during the COVID-19 pandemic. We also provide the first within-subject comparison between neurodevelopmental tics and functional tics, to assist clinicians in the differential diagnosis of patients with TS who developed a functional overlay during challenging times.