Gilles da la Tourette syndrome (TS)* is a common chronic neuropsychiatric disorder characterized by motor and vocal tics. In most adult patients, quality of life is significantly impaired. TS, therefore, is a cost-intensive disease (in Germany: mean total costs=€3404/year). Despite significant adverse effects, dopamine receptor antagonists were recommended as first choice treatment for many years. Although efficacy could be demonstrated only recently, today, behavioral therapy with face-to-face Comprehensive Behavioral Intervention for Tics (CBIT) (including psychoeducation, habit reversal training, function-based assessment and intervention, and relaxation training) is recommended as first line treatment for tics. In Germany, however, dissemination of CBIT is restricted due to a considerable lack of well-trained therapists. The aim of this study is to overcome this deficiency by creating a new and sophisticated internet-delivered CBIT (iCBIT) program. In addition, internet-delivered CBIT will shorten waiting time, will reach additional groups of patients and will be - once developed and established - highly cost-effective (about € 100 vs. € 1450 for face-to-face CBIT). Investigators want to perform a multicenter, randomized, controlled, observer-blind trial including 160 adult patients in order to demonstrate that 8 sessions (10 weeks) of iCBIT are superior to internet-delivered psychoeducation/relaxation in adult patients with TS. Both immediate (1 week after end of treatment) and long-term effects (after 3 and 6 months) will be evaluated.

Inclusion Criteria:

• Chronic tic disorder or Tourette syndrome according to DSM-5
• Age ≥18 years; Yale Global Tic Severity Scale (YGTSS) total tic score (TTS) > 14 or > 10 (for patients only with motor or vocal tics)
• Clinical Global Impression-Severity Score (CGI-S) > 4
• Medication for tics and comorbidities must be on a stable dose for at least 6 weeks before entering the study
• Fluent German in speaking and writing
• Ability to give informed consent and signed informed consent

Exclusion Criteria:

• History of schizophrenia or pervasive developmental disorder
• Comorbid obsessive-compulsive disorder (OCD), attention deficit hyperactivity disorder (ADHD), depression, anxiety disorder when unstable and/or in need of an initial adjustment for a therapy
• History of behavioral treatment for tics
• Current illicit substance abuse or addiction (clinically diagnosed)
• Secondary tic disorder or other significant neurological and psychiatric disease
• No internet access or ability to use the internet
• Participation in a study with medicinal products or devices is not allowed within 6 weeks before inclusion or concurrent to this study