Expert reviews and practice parameter papers recommend behavior therapy as a first-line intervention for youth with chronic tic disorders (CTDs) with mild-to-moderate tic severity. Although behavior therapies like the Comprehensive Behavioral Intervention for Tics (CBIT) are efficacious in reducing tic symptom severity, only 50% of individuals exhibit a positive treatment response. Thus, there is a clear need to identify strategies to improve treatment response and/or accelerate therapeutic gains .

The primary ingredient of CBIT is habit reversal training (HRT), which utilizes both extinction and associative learning. Psychosocial treatments relying on these learning mechanisms have demonstrated an enhanced and/or expedited therapeutic benefit when augmented with d-cycloserine (DCS). This feasibility study will examine the incremental efficacy of HRT+DCS over HRT+placebo for tics targeted with HRT. Eligibility criteria will parallel the child CBIT trial for generalizability and comparability, with the addition of DCS contraindications as exclusionary criteria. Parents and youth will complete a battery of clinical assessments to ascertain tic symptoms severity and co-occurring psychiatric conditions. Afterwards, participants will be randomly assigned to receive either HRT+DCS or HRT+placebo. Instead of a full course of HRT (8 sessions over 10 weeks), a more efficient Quick-Win/Fast-Fail trial design will be used that includes a truncated HRT protocol to provide results in a more timely fashion. As a result of this trial design, the primary outcome of this study will focus on the reduction of bothersome tic severity for those targeted in treatment rather than global severity reductions.

Expert reviews and practice parameter papers recommend behavior therapy as a first-line intervention for youth with chronic tic disorders (CTDs) with mild-to-moderate tic severity. Although behavior therapies like the Comprehensive Behavioral Intervention for Tics (CBIT) are efficacious in reducing tic symptom severity, only 50% of individuals exhibit a positive treatment response. Thus, there is a clear need to identify strategies to improve treatment response and/or accelerate therapeutic gains. The primary ingredient of CBIT is habit reversal training (HRT), which utilizes both extinction and associative learning. Psychosocial treatments relying on these learning mechanisms have demonstrated an enhanced and/or expedited therapeutic benefit when augmented with d-cycloserine (DCS). This feasibility study will examine the incremental efficacy of HRT+DCS over HRT+placebo for tics targeted with HRT. Eligibility criteria will parallel the child CBIT trial for generalizability and comparability, with the addition of DCS contraindications as exclusionary criteria. Parents and youth will complete a battery of clinical assessments to ascertain tic symptoms severity and co-occurring psychiatric conditions. Afterwards, participants will be randomly assigned to receive either HRT+DCS or HRT+placebo. Instead of a full course of HRT (8 sessions over 10 weeks), a more efficient Quick-Win/Fast-Fail trial design will be used that includes a truncated HRT protocol to provide results in a more timely fashion. As a result of this trial design, the primary outcome of this study will focus on the reduction of bothersome tic severity for those targeted in treatment rather than global severity reductions.

Inclusion Criteria:

1. ages 8 years to 17 years (inclusive);
2. meet diagnostic criteria for either Tourette Disorder or a Persistent Tic Disorder;
3. moderate tic severity or greater as evidenced by a Yale Global Tic Severity Scale (Leckman, Riddle, Hardin, & Ort, 1989) total score greater than 13 (>9 for children with motor or vocal tics only);
4. be fluent in English;
5. be medication free or on a stable dose of a non-antipsychotic medication for 6 weeks with no planned changes.

Exclusion Criteria:

1. pregnant or breast feeding;
2. an unstable medical condition (e.g., a seizure disorder, kidney or liver disease);
3. current diagnosis of substance abuse/dependence;
4. lifetime diagnosis of schizophrenia, autism spectrum disorder, bipolar disorder, or psychosis;
5. evidence of a seizure disorder, kidney or liver disease, pregnant and/or breast feeding;
6. four or more previous sessions of HRT; or
7. currently taking an antipsychotic medication.

Immediately after therapy session (Visit 2) and 1 week after therapy session (Visit 3)

Adverse events were systematically assessed at Visits 2 and 3 using side effect review form derived from the Safety Monitoring Uniform Report Form (SMURF).