Effectiveness of Behaviour Therapy for Children and Adolescents with Tourette Syndrome and Chronic Tic Disorder in a Naturalistic Setting.

It is unclear if the results of randomised controlled trials (RCTs) of behaviour therapy (BT) for Tourette syndrome (TS) and chronic tic disorder (CTD) can be generalised to naturalistic clinical settings and are durable long-term. In this naturalistic study, 74 young people with TS/CTD received BT at a specialist clinic. Data were collected at baseline, post-treatment, and at 3-, 6-, and 12-month follow-ups. Measures included the Yale Global Tic Severity Scale (YGTSS) and the Clinical Global Impression-Improvement scale (CGI-I), amongst others. Tic severity and tic-related impairment improved after treatment, with large within-group effect sizes. At post-treatment, 57% of the participants were classified as treatment responders according to the CGI-I. Tic severity and tic-related impairment improved further through the follow-up, with 75% treatment responders at the 12-month follow-up. BT is an effective and durable treatment for young people with TS/CTD in a naturalistic specialist clinical setting, with comparable effects to RCTs.