Introduction Tourette syndrome (TS) is a childhood–onset neurodevelopmental disorder characterised by chronic multiple motor and vocal tics associated with other co–morbidities in most cases. The natural course is for symptoms to fluctuate according to situation with underlying waxing and waning in severity over weeks, months and years. Case reports have described distinct bouts of severe, continuous, non–suppressible and disabling tics lasting from 15 minutes to several hours, events known synonymously as “tic status”, “tic attacks” or “tic fits”. These events are described more often in patient forums than in a very small literature. This study documents the prevalence and clinical features of these attacks in a tertiary clinic cohort and investigates the relationship between tic attacks, the severity of underlying TS and the presence of associated co–morbidities.

Methods Clinical records of 369 patients were retrospectively examined for descriptions of tic attacks ie. clinically disabling bouts of non–suppressible repetitive tics occurring in full consciousness. The clinical features of the attacks were recorded. These patients were compared to a control group of the remaining 337 patients in terms of age, gender, presence of associated co–morbidities and TS severity.

Results 32 patients with tic attacks were identified (8.7%). This is likely to be an underestimate as relies on clinical assessments which may not have included systematic enquiry on this point. Duration of attacks was from 3 minutes up to 3 hours. Reported provoking factors included periods of increased obsessive compulsive symptomatology and preceding prolonged suppression of tics for instance at bedtime in children. Tic attacks had necessitated the introduction of PRN medication and emergency hospital attendance in several of the patients. Patients with tic attacks were significantly younger than control TS patients (mean 14 v. 20 years) and more likely to be in the age range 10–19 years (72% v. 41%). Patients in the tic attack group had significantly more co–morbid attention deficit hyperactivity disorder (56% v 29%) but other common co–morbidities (obsessive compulsive disorder, oppositional defiant disorder (in children) and mood disorders) were present at similar rates in both groups. Tic attacks were associated with TS of greater underlying severity as measured on the Yale Global Tic Severity Score (31 v. 25), and clinician rating as “severe” in 46% v. 15%.

Discussion Tic attacks are much more common in a tertiary clinic cohort than previously thought, and this may become more apparent if the symptom is prospectively sought. The term can be attached to episodes down to short durations that may not be far outwith the normally expected range of the condition and so is not clinically homogeneous. However, tic attacks cause particular alarm or disability and have the potential to be mistaken for epileptic seizures, a problem that has certainly occurred in practice. An association with ADHD could reflect a shared aetiological substrate but as ADHD is more common in more severe TS cases the explanation could be less specific.