ABSTRACT
Background and purpose: Over the past year, many cases with newly onset or significantly exacerbated tic disorders were observed worldwide, where some aspects of the clinical presentation or the symptomatology were atypical for established tic diagnoses. Our purpose was to describe the atypical cases and raise relevant diagnostic issues. Methods: Consecutive cases with atypical tic presentations were documented. Results: Five atypical tic cases are described. These cases shared some common characteristics, most notably the fact that all of them had been exposed to online presentation of ticking behaviour on social media platforms prior to the de novo development or exacerbation of their tics. Even though the order of events suggests causality and therefore the diagnosis of a functional tic disorder, unambiguous criteria for classifying atypical tics as functional symptoms are lacking. Differentiating neurodevelopmental and functional tics in childhood is currently problematic. Conclusion: Based on the currently unresolved issues in differential diagnosis, the importance of watchful waiting and behavioural interventions is highlighted to avoid unwarranted pharmacotherapy.