To evaluate the effect and acceptability of an Internet-based comprehensive behavioral intervention for tics (ICBIT) in a sample of children and adolescents with Tic disorders. children and adolescents (aged 8-17 years) with Tourette Syndrome (TS) or Chronic Tic Disorder (CTD) and their parents will be randomly assigned to receive either an Internet-based ICBIT or wait-list (WL).

To evaluate the effect and acceptability of an Internet-based comprehensive behavioral intervention for tics (ICBIT) in a sample of children and adolescents with Tic disorders, children and adolescents (aged 8-17 years) with Tourette Syndrome (TS) or Chronic Tic Disorder (CTD) and their parents will be randomly assigned to receive either an Internet-based ICBIT or wait-list (WL) condition in a cross over design.

Participants will be randomized to ICBIT, or to wait list, and half will cross over from wait list to ICBT. Two blind independent clinical evaluators will rate tic severity and comorbidity. The primary outcome measure is the Yale Global Tic Severity Scale (YGTSS). Assessments will be performed at baseline, post-ICBT or post wait list, 3-months and 6-months (post-treatment for those originally assigned to ICBT) and post-ICBT, 3-months and 6-months (post-treatment for those originally assigned to wait list condition). All assessments were conducted by 2 PhD level independent child psychologists.

Inclusion Criteria:

• Clinical diagnosis of Tourette Syndrome or Chronic Tic Disorder.
• Yale Global Tic Severity Scale tic severity score ≥14.

Exclusion Criteria:

• Change in psychotropic medication regimen during the past 6 weeks.
• Current diagnosis of substance abuse/dependence.
• Lifetime diagnosis of pervasive developmental disorder, mania or psychosis.
• Previous sessions of CBIT.