Functional tics and tic-like behaviors

Functional tics and tic-like behaviors belong to the wide spectrum of functional movement disorders. Until the early 2010s, functional tic disorders were rather uncommon in the differential diagnosis of tics, and only few cases describing their features had been published. However, over the past 10 years there has been a steady increase in the frequency of these cases that peaked throughout the COVID-19 pandemic. On the one hand, the rise in functional tic cases created new challenges of diagnosis and treatment. At the same time, it also pushed the field forward to delineate helpful clinical clues, as well as to work toward specific consensus diagnostic criteria for functional tics and tic-like behaviors. Here, we first provide a historical summary on the debate between neurodevelopmental and functional tics. We then track relevant literature on functional tics and tic-like cases and discuss their salient features, such as an acute onset with severe symptoms and complex repetitive behaviors that typically occur in late adolescence or early adulthood, a large variability of symptoms including spontaneous symptom remissions and re-emergence, and a high prevalence of phonations and vocalizations with the common use of swearwords or variable sentences. In addition, it is common to see an overlap with additional functional neurologic symptoms, such as functional tremor or nonepileptic seizures. In diagnostically challenging cases, neurophysiologic evaluation, including surface electromyography and electroencephalography, may be useful, and markers such as the premotor potential (Bereitschaftspotential) and event-related desynchronization/synchronization may hold promise. Effective management of functional tics begins with an accurate diagnosis and often requires a multidisciplinary approach. Cognitive-behavioral therapy and the Comprehensive Behavioral Intervention for Tics may be particularly useful, alongside addressing comorbid psychiatric conditions. Currently there is an absence of standardized treatment protocols; individualized care plans tailored to each patient's specific needs are generally the most effective approach.