Tourettes Disorder (TD) is characterized by tics that cause distress and impairment. While treatment guidelines recommend behavior therapy as a first-line intervention, patients with TD may exhibit limited therapeutic response. Given the need to improve treatment outcomes, this study examined the efficacy of augmenting behavior therapy with D-cycloserine (DCS) to reduce tic severity in a placebo-controlled quick-win/fast-fail trial. Twenty youth with TD completed a baseline assessment to characterize tic severity, premonitory urges, medical history, and psychiatric comorbidity. Youth were randomly assigned to receive a single session of habit reversal training (HRT) augmented by either 50 mg of DCS or placebo. Two bothersome tics on the Hopkins Motor/Vocal Tic Scale (HM/VTS) were targeted for treatment during HRT. One week after the HRT session, youth completed a posttreatment assessment to evaluate change in the severity of bothersome tics. All assessments were completed by independent evaluators masked to treatment group. There was a Treatment Group by Time Interaction in favor of DCS-augmented HRT (p < 0.01), controlling for baseline tic severity, tic medication, and attention deficit hyperactivity disorder. Follow-up comparisons revealed small group differences at the treatment visit (d = 0.27), with the DCS group exhibiting slightly greater severity for targeted tics. There was a large group difference at posttreatment, in which the DCS group exhibited lower severity for targeted tics (d = 1.30, p < 0.001) relative to the placebo group. Findings demonstrate the preliminary enhancement of tic severity reductions by augmenting HRT with DCS compared with placebo augmentation.

Behavior therapy is a first-line intervention for Tourette's Disorder (TD), and a key component is the practice of therapeutic skills between treatment visits (i.e., homework). This study examined the relationship between homework adherence during behavior therapy for TD and therapeutic outcomes, and explored baseline predictors of homework adherence during treatment. Participants included 119 individuals with TD (70 youth, 49 adults) who received behavior therapy in a clinical trial. After a baseline assessment of tic severity and clinical characteristics, participants received 8 sessions of behavior therapy. Therapists recorded homework adherence at each therapy session. After treatment, tic severity was re-assessed by independent evaluators masked to treatment condition. Greater overall homework adherence predicted tic severity reductions and treatment response across participants. Early homework adherence predicted therapeutic improvement in youth, whereas late adherence predicted improvement in adults. Baseline predictors of greater homework adherence in youth included lower hyperactivity/impulsivity and caregiver strain. Meanwhile in adults, baseline predictors of increased homework adherence included younger age, lower hyperactivity/impulsivity, obsessive-compulsive severity, anger, and greater work-related disability. Homework adherence is an integral component of behavior therapy and linked to therapeutic improvement. Strategies that improve homework adherence may optimize the efficacy of behavioral treatments and improve treatment outcomes.

Background

Individuals with Tourette Syndrome and Persistent Tic Disorders (collectively TS) often experience premonitory urges-aversive physical sensations that precede tics and are temporarily relieved by tic expression. The relationship between tics and premonitory urges plays a key role in the neurobehavioral treatment model of TS, which underlies first-line treatments such as the Comprehensive Behavioral Intervention for Tics (CBIT). Despite the efficacy of CBIT and related behavioral therapies, less than 40% of adults with TS respond to these treatments. Further examination of the relationship between premonitory urges, tic severity, and tic impairment can provide new insights into therapeutic targets to optimize behavioral treatment outcomes. This study examined whether urge intolerance-difficulty tolerating premonitory urges-predicted tic severity and tic-related impairment among adults with TS.

Methods

Participants were 80 adults with TS. Assessments characterized premonitory urge, distress tolerance, tic severity, and tic impairment. We used structural equation modeling (SEM) to examine the construct of urge intolerance-comprised of premonitory urge ratings and distress tolerance ratings. We first evaluated a measurement model of urge intolerance through bifactor modeling, including tests of the incremental value of subfactors that reflect premonitory urge severity and distress tolerance within the model. We then evaluated a structural model where we predicted clinician-rated tic severity and tic impairment by the latent variable of urge intolerance established in our measurement model.

Results

Analyses supported a bifactor measurement model of urge intolerance among adults with TS. Consistent with theoretical models, higher levels of urge intolerance predicted greater levels of clinician-rated tic severity and tic impairment.

Conclusion

This investigation supports the construct of urge intolerance among adults with TS and distinguishes it from subcomponents of urge severity and distress tolerance. Given its predictive relationship with tic severity and tic impairment, urge intolerance represents a promising treatment target to improve therapeutic outcomes in adults with TS.

Objective

Treatment guidelines for Tourette's Disorder (TD) are based on patients' degree of tic severity and impairment. However, clear benchmarks for determining tic severity and impairment have not been established. This study examined benchmarks of tic severity and tic impairment using the Yale Global Tic Severity Scale (YGTSS) and the Clinical Global Impression of Severity (CGI-S).

Method

Individuals with TD or another Tic Disorder (N = 519) recruited across nine sites were administered a diagnostic interview, the YGTSS, and the CGI-S. Correlations and trend analyses contrasted YGTSS scores across CGI-S ratings. A logistic regression model examined predictive benchmarks for tic severity, tic impairment, and global severity. Model classifications were compared against CGI-S ratings, and agreement was examined using kappa.

Results

Spearman correlations between the CGI-S and YGTSS scores ranged from 0.54 to 0.63 (p < 0.001). Greater CGI-S ratings were associated with a linear stepwise increase in YGTSS Total Tic scores, Impairment scores, and Global Severity scores. Despite moderate-to-strong associations (ρ = 0.45-0.56, p < 0.001) between the CGI-S and predictive logistical regression models, only fair agreement was achieved when applying classification benchmarks (κ = 0.21-0.32, p < 0.001).

Conclusions

CGI-S ratings are useful to characterize benchmarks for tic severity, tic impairment, and global severity on the YGTSS. Logistic regression model benchmarks had only fair agreement with the CGI-S and underscore the heterogeneity of TD symptoms. Collectively, findings offer guidance on the delineation of tic severity categorizations to apply evidence-based treatment recommendations.