Objective Functional tics, also called psychogenic tics or pseudo-tics, are difficult to diagnose because of the lack of diagnostic criteria and their clinical similarities to organic tics. The aim of the present study was to report a case series of patients with documented functional tics and to describe their clinical characteristics, risk factors and psychiatric comorbidity. We also suggest clinical tips which might help the differential diagnosis in clinical practice.

Method All the patients diagnosed with functional tics between January 2011 and October 2013 in the movement disorders clinic and in the Tourette clinic of the National Hospital for Neurology and Neurosurgery (NHNN), London were reviewed.

Results We included 11 patients (mean age at onset 37.2, SD 13.5; three females) with a documented or clinically established diagnosis of functional tics, according to consultant neurologists who have specific expertise in functional movement disorders or in tic disorders. Adult onset, absent family history of tics, inability to suppress the movements, lack of premonitory sensations, absence of pali-, echo- and coprophenomena, presence of blocking tics, the lack of the typical rostrocaudal tic distribution and the coexistence of other functional movement disorders were common in our patients.

Conclusion Our data suggest that functional tics can be differentiated from organic tics on clinical grounds, though we also accept that this distinction can be difficult in certain cases. Clinical clues from history and examination described here might help to identify patients with functional tics.