Rapid onset of functional tic-like behaviours in young adults during the COVID-19 pandemic

Background and purpose Clinicians have reported an increase in functional tic-like behaviours in children and youth during the COVID-19 pandemic. We describe adults developing rapid onset of functional tic-like behaviours between May 2020 and June 2021. Methods Data were analysed from the Adult Tic Disorders Registry, a single-site,12-month prospective cohort study that began enrolment in January 2021. We compared clinical features of participants with Tourette syndrome or persistent motor/vocal tic disorder to participants with rapid onset tic-like behaviours. Results Thirty-three participants registered between January and June of 2021; nine had rapid onset tic-like behaviours, and 24 had Tourette syndrome or persistent motor tic disorder. Participants with rapid onset tic-like behaviours were younger (19.9 vs. 38.6 years, p = 0.003), had older age at onset (15.3 vs. 10.1, p = 0.0009), and were more likely female (p < 0.0001). They had higher motor and vocal tic severity and impairment scores (all p < 0.01) and were more likely to have complex arm/hand motor tics (p < 0.0001), complex vocal tics (p < 0.0001), and coprolalia (p = 0.004). They had significantly higher scores on all mental health symptom self-report measures (all p < 0.05) and were significantly more likely to be diagnosed with depression (p = 0.03). Conclusions The clinical features that help differentiate rapid onset tic-like behaviours from Tourette syndrome or persistent motor tic disorder include their phenomenology, onset age, and clinical course. Rapid onset tic-like behaviours are a distinct subtype of functional neurological disorder that has emerged during the COVID-19 pandemic in young people and appears to be strongly socially influenced.