Efficacy and cost-effectiveness of therapist-guided internet-delivered behaviour therapy for children and adolescents with Tourette syndrome: study protocol for a single-blind randomised controlled trial.

backgroundTreatment guidelines recommend behaviour therapy (BT) for patients with Tourette syndrome (TS) and chronic tic disorder (CTD). However, BT is rarely accessible due to limited availability of trained therapists and long travel distances to specialist clinics. Internet-delivered BT has the potential of overcoming these barriers through remote delivery of treatment with minimal therapist support. In the current protocol, we outline the design and methods of a randomised controlled trial (RCT) evaluating an internet-delivered BT programme referred to as BIP TIC. The trial's primary objective is to determine the clinical efficacy of BIP TIC for reducing tic severity in young people with TS/CTD, compared with an active control intervention. Secondary objectives are to investigate the 12-month durability of the treatment effects and to perform a health economic evaluation of the intervention.

methodsIn this single-blind superiority RCT, 220 participants (9-17 years) with TS/CTD throughout Sweden will be randomised to 10-12 weeks of either therapist-supported internet-delivered BT based on exposure with response prevention (BIP TIC) or therapist-supported internet-delivered education. Data will be collected at baseline, 3 and 5 weeks into the treatment, at post-treatment, and 3, 6, and 12 months post-treatment. The primary endpoint is the 3-month follow-up. The primary outcome is tic severity as measured by the Yale Global Tic Severity Scale - Total Tic Severity Score. Treatment response is operationalised as scores of "Very much improved" or "Much improved" on the Clinical Global Impression - Improvement scale, administered at the primary endpoint. Outcome assessors will be blind to treatment condition at all assessment points. A health economic evaluation of BIP TIC will be performed, both in the short term (primary endpoint) and the long term (12-month follow-up). There are no planned interim analyses. DISCUSSION: Participant recruitment started on 26 April 2019 and finished on 9 April 2021. The total number of included participants was 221. The final participant is expected to reach the primary endpoint in September 2021 and the 12-month follow-up in June 2022. Data analysis for the primary objective will commence after the last participant reaches the primary endpoint.

trial registrationClinicalTrials.gov NCT03916055 . Registered on 16 April 2019.