Therapist-Supported Internet-Delivered Exposure and Response Prevention for Children and Adolescents With Tourette Syndrome: A Randomized Clinical Trial.

The availability of behavior therapy for individuals with Tourette syndrome (TS) and chronic tic disorder (CTD) is limited. To determine the efficacy and cost-effectiveness of internet-delivered exposure and response prevention (ERP) for children and adolescents with TS or CTD. This single-masked, parallel group, superiority randomized clinical trial with nationwide recruitment was conducted at a research clinic in Stockholm, Sweden. Out of 615 individuals assessed for eligibility, 221 participants meeting diagnostic criteria for TS or CTD and aged 9 to 17 years were included in the study. Enrollment began in April 2019 and ended in April 2021. Data were analyzed between October 2021 and March 2022. Participants were randomized to 10 weeks of therapist-supported internet-delivered ERP for tics (111 participants) or to therapist-supported internet-delivered education for tics (comparator group, 110 participants). The primary outcome was change in tic severity from baseline to the 3-month follow-up as measured by the Total Tic Severity Score of the Yale Global Tic Severity Scale (YGTSS-TTSS). YGTSS-TTSS assessors were masked to treatment allocation. Treatment response was operationalized as a score of 1 ("Very much improved") or 2 ("Much improved") on the Clinical Global Impression-Improvement scale. Data loss was minimal, with 216 of 221 participants (97.7%) providing primary outcome data. Among randomized participants (152 [68.8%] boys; mean [SD] age, 12.1 [2.3] years), tic severity improved significantly, with a mean reduction of 6.08 points on the YGTSS-TTSS in the ERP group (mean [SD] at baseline, 22.25 [5.60]; at 3-month follow-up, 16.17 [6.82]) and 5.29 in the comparator (mean [SD] at baseline, 23.01 [5.92]; at 3-month follow-up, 17.72 [7.11]). Intention-to-treat analyses showed that the 2 groups improved similarly over time (interaction effect, -0.53; 95% CI, -1.28 to 0.22; P = .17). Significantly more participants were classified as treatment responders in the ERP group (51 of 108 [47.2%]) than in the comparator group (31 of 108 [28.7%]) at the 3-month follow-up (odds ratio, 2.22; 95% CI, 1.27 to 3.90). ERP resulted in more treatment responders at little additional cost compared with structured education. The incremental cost per quality-adjusted life-year gained was below the Swedish willingness-to-pay threshold, at which ERP had a 66% to 76% probability of being cost-effective. Both interventions were associated with clinically meaningful improvements in tic severity, but ERP led to higher response rates at little additional cost. ClinicalTrials.gov identifier: NCT03916055.