Overview

HRT is a multi-component behavioral therapy that aims to reduce tic severity by disrupting the negative reinforcement cycle that contributes to tic expression (ie, urge→tic→relief; see Essoe and colleagues for further discussion for mechanisms underlying behavior therapy). Although HRT can consist of several therapeutic components, the 3 core components of HRT are: (1) awareness training, (2) competing response training, and (3) social support. Awareness training involves increasing awareness of tic occurrence. This can include the identification of the physical expression of the tic, early tic movements, and/or premonitory urge that precedes tic occurrence. Competing responses are voluntary behaviors that are physically incompatible with the targeted tic (eg, subtly squinting eyes for eye widening tics), which are implemented contingent upon tic awareness by the patient. Competing responses are ideally discreet (in comparison with the targeted tic) and sustainable for periods of time, so that patients can implement them while maintaining participation in their routine activities. Social support consists of regular practice of tic awareness and competing responses with individuals close to the patient (eg, family members, caregivers, partners, and friends). Specific praises and reminders to reinforce the use of these skills are often utilized based on the developmental level of the patient. ^, Social support helps patients develop competence and confidence implementing therapeutic strategies across individuals and settings. While HRT sessions typically last up to 60 minutes and occur on a weekly basis, the duration of treatment and its delivery can vary greatly based on the clinical presentation and tic severity of the patient.

Empirical Support

In case studies, HRT has been shown to be beneficial for children as young as 6 and adults as old as 75 years of age. Notably, HRT has been tested in several randomized controlled trials (RCTs) of varying sizes and methodological qualities. To date, there have been at least 5 RCTs that have compared HRT to waitlist conditions, control treatments (eg, massed negative practice and psychoeducation with supportive therapy ^, ), and active treatments (eg, ERP). In RCTs comparing waitlist and control treatments, HRT has demonstrated superior efficacy for reducing tic frequency and/or tic severity with sustained benefit lasting up to 10 months on evidence-based rating scales. While HRT was found to produce comparable reductions in tic severity relative to ERP, the caveat is that participants in the ERP condition received 12 two-hour weekly therapy sessions whereas participants in the HRT condition only received 10 one-hour weekly sessions.

Despite some concerns about “tic contagion,” HRT has been efficaciously delivered in a group-treatment format. HRT has also been combined with different therapeutic strategies such as cognitive therapy, ^, acceptance and commitment therapy (ACT), and even ERP. Initial evidence suggests that the addition of cognitive therapy and ACT do not provide any additive benefit above and beyond HRT. ^, While neither HRT or ERP has shown definitive benefit over the other for reducing tic severity, further research is needed to better understand the combination of these 2 related therapeutic strategies.

Limitations

While HRT has shown benefit for reducing tic severity and tic-related impairment, several limitations exist. Perhaps most notably, HRT primarily focuses on the implementation of competing responses contingent upon internal antecedents and/or consequences that influence tic expression (eg, premonitory urges) and does not directly incorporate therapeutic strategies to address external antecedents and/or consequences related to tics (eg, contextual factors, situations, and/or activities that increase tic expression). ^,

Overview

CBIT is an extension of HRT but includes 2 additional core therapeutic components: (1) relaxation training and (2) a functional assessment with functional interventions. Relaxation training includes therapeutic strategies such as diaphragmatic breathing and progressive muscle relaxation, which aim to reduce stress and muscle tension related to tic expression. Meanwhile, functional assessments are utilized to determine antecedents (eg, situations, activities, and/or environmental factors) and consequences (eg, reinforcement, avoidance) that influence tic expression. These assessments inform the development of individualized function-based behavioral interventions to reduce the influence of identified antecedents on tic expression. For example, if a child exhibited increased tics when completing homework, a caregiver may allow the child to discontinue the activity to alleviate short-term tic expression. However, this may unintentionally reinforce tic expression the next time homework is completed. Functional assessments and interventions would identify this antecedent activity and implement behavioral strategies to reduce the long-term tic expression.

Empirical Support

There have been at least 2 multisite RCTs that have compared CBIT to psychoeducation with supportive therapy in children ( n = 126) and adults ( n = 122). These multisite RCTs found that CBIT significantly reduced tic severity and tic-related impairment for both children and adults on the Yale Global Tic Severity Scale (YGTSS)—the gold-standard measure of tic severity and impairment. ^, There was no evidence of symptom substation (ie, successful treatment of one tic being replaced by a new tic), with CBIT found to be beneficial for many bothersome tics. ^, For CBIT treatment responders, therapeutic gains were maintained for up to 6-months posttreatment for children and adults, with homework adherence to CBIT strategies found to predict treatment response. Perhaps most notably, CBIT treatment responders were found to continue to exhibit therapeutic improvement almost 11 years after initial treatment (ie, 8 sessions over a 10-week period) and were more likely to experience tic remission in adulthood.

CBIT has been adapted for children as young as 5 years old and found to be efficacious. It has also been modified to be delivered in group formats, intensive formats, ^, online platforms, ^, and over telehealth. While initial evidence suggests that intensive and telehealth approaches produce similar outcomes to weekly in-person CBIT sessions, smaller treatment effects have been observed from delivery in a group format and online platforms—which have minimal to no therapist support. Further research in large studies is needed to better understand which CBIT delivery approaches are most appropriate for which patients.

Limitations

While CBIT has shown efficacy for reducing tic severity, a few limitations exist. First, despite its robust and durable reduction in tic severity, not all patients who receive CBIT experience a treatment response (38% of adults and 53% of children in RCTs). ^, While ADHD and alpha-agonists have been found to moderate treatment response to CBIT, ^, cognitive control processes do not consistently predict tic severity reductions ^, —indicating that even youth with impaired cognitive control can still benefit from CBIT. Therefore, there is a clear need to identify the precise mechanisms underlying CBIT that can be used to inform therapeutic strategies that can optimize treatment outcomes. Second, CBIT (and other behavioral therapies) are often inaccessible to patients with TS—primarily due to the limited number of trained providers. Indeed, fewer than 25% of youth with TS receive evidence-based behavior therapy, ^, with less than 10% of urban-based mental health providers having received any training in behavior therapy for TS. Thus, there is clear room to improve the accessibility (and availability) of behavior therapies for TS.

Overview

ERP for tics is a behavioral intervention which includes 2 core components: (1) exposure to premonitory urges and (2) tic suppression (called response prevention) that aims to disrupt the negative reinforcement cycle that maintains tic expression. In ERP sessions, patients practice suppressing tics for increasingly longer periods of time with the degree of difficulty increased in a step-wise fashion during later sessions (ie, increased focus on eliciting premonitory urges and engagement in simultaneous tic suppression). ERP is notably different than HRT or CBIT in that it focuses on tic suppression rather than using competing behavioral responses to inhibit tic expression.

Empirical Support

There have been relatively few RCTs examining the efficacy of ERP in TS. In a head-to-head RCT that compared ERP to HRT, ERP was found to reduce tic severity on the YGTSS and showed comparable reductions to HRT. However, as noted above, participants in the ERP group had approximately twice the therapeutic contact of HRT group. On balance, a small open-label trial compared shorter ERP sessions (1 hour) to the traditionally prolonged sessions (2 hours) and found comparable reduction in tic severity.

RCTs have also examined the efficacy of the online remote delivery of ERP with parent assistance and/or minimal therapist support compared with remote control conditions (eg, psychoeducation) for youth with TS. This online delivery of ERP has shown efficacy for reducing tic severity compared with the online remote control conditions. However, the therapeutic benefit from the online delivery of ERP was generally more modest than traditional face-to-face care. Finally, given its similarities, ERP and HRT have been combined and delivered in group formats as previously noted.

Limitations

While ERP has shown efficacy for reducing tic severity, there are a few aspects that warrant consideration. First, there are few studies assessing the sustained benefit of ERP for reducing tic severity. While one report that combined ERP with HRT found sustained benefit on tic severity outcomes after 1 year, there have been no published RCTs evaluating the long-term durability (greater than 1 year) of ERP alone on tic severity outcomes. Second, ERP utilizes tic suppression as its core therapeutic strategy to reduce tic expression. There is some evidence that attentional performance is reduced on other activities (eg, taking tests) when youth are engaged in simultaneous tic suppression. Other factors may also influence tic suppression capabilities such as contextual factors (eg, activities and/or environment), demographic factors (eg, age), mental health (eg, stress), and tic severity (eg, tic frequency). ^{, ,} On balance, many youth and adults with TS report successfully engaging in tic suppression across a variety of daily activities. Thus, future research is needed to better understand the mechanisms underlying tic suppression, which can inform therapeutic strategies to improve ERP outcomes. ^,

Accessibility of Treatment

Historically, behavior therapy has been delivered via face-to-face in weekly therapy sessions. As a result, fewer than 25% of youth with TS receive evidence-based behavior therapy ^, largely due to the accessibility of the limited number of trained providers. New treatment-adapted delivery formats (eg, intensive, group, and telehealth) have improved the accessibility of behavior therapy for TS, but remain encumbered by the availability of trained therapists. While online delivery platforms (eg, ORBIT, iCBIT) have reduced the demand on therapists to improve accessibility of behavior therapy, the tic severity reductions have been more modest from this delivery approach. Beyond this, extant online interventions are entirely delivered using computers that can be challenging for some patients with TS (ie, sustained attention in front of a computer screen) and still may be limited in access throughout the day (ie, limited accessibility of computers throughout the day). In contrast, digital health interventions delivered on smartphones are widely accessible and have shown considerable promise as standalone interventions for related conditions (eg, anxiety and depression). Thus, the adaptation and delivery of behavior therapy directly to individuals with TS (or with parental support) could serve as an accessible, practical, and scalable “first-line” treatment approach for patients with TS who are waiting to receive face-to-face care.

Investigating Treatment Mechanisms and Optimizing Outcomes

As described earlier, there is still considerably more research needed to delineate the precise mechanisms underlying behavioral therapies. The identification of treatment mechanisms can provide key insights to optimize tic severity reductions and improve treatment response rates from behavior therapy. For instance, associative learning processes (eg, reinforcement learning) and cognitive control processes (eg, inhibition) have been implicated as a key mechanism in the neurobehavioral model of tics (eg, urge→tic→relief cycle). A small Quick-Win/Fast-Fail RCT found that enhancing HRT with a cognitive enhancer ( d -cycloserine) improved therapeutic outcomes for targeted tics. Meanwhile, other investigations have found that CBIT improves inhibitory control—such that no significant difference is identifiable between unaffected individuals and youth with TS on standardized inhibitory tasks after CBIT. Although transcranial magnetic stimulation (TMS) alone does not significantly reduce tic severity in RCTs, emerging research is exploring pairing TMS with behavior therapy to enhance treatment outcomes. ^, While considerable more research is needed to fully elucidate underlying mechanisms, initial findings and ongoing research hold considerable promise to advance the field and improve tic severity reductions.

Treatments for the Whole Person

A considerable percentage of patients with TS do not experience a clinically meaningful reduction in tic severity (ie, a treatment response), and many adults whose tics have diminished continue to report impairment from childhood tics. As such, there is a clear need to help patients with TS manage and overcome the psychosocial challenges that often accompany tics. However, current behavioral therapies (eg, HRT, CBIT, and ERP) are entirely focused on tic severity outcomes and do not confer direct benefit to common comorbid conditions and/or related psychosocial challenges (eg, treating tics may not directly improve self-esteem, self-concept, and/or address social difficulties related to tics). Thus, new behavioral and psychosocial interventions are needed to comprehensively reduce tic severity and tic-related impairment, improve quality of life, diminish the severity of comorbid conditions, and cultivate resilience. There are several promising new treatments that have been examined in initial research and show some promise. For instance, McGuire and colleagues (2015) developed a modularized cognitive behavioral intervention that included HRT strategies but focused treatment strategies on reducing tic-related impairment and developing skills to manage the psychosocial consequences of tics. In an RCT, this modular treatment (called Living with Tics) resulted in reduced tic-related impairment and improved quality of life with therapeutic gains maintained at follow-up. Although just one example, other innovative treatments that treat the whole person have also been examined (eg, mindfulness; see Reese and colleagues’ article, “ Mindfulness-based Interventions for Tourette Syndrome: Current Status and Future Directions ,” in this issue for further discussion of mindfulness for TS). Notably, further research is needed to build upon these promising initial findings and also to develop new treatment approaches to improve the lives of patients with TS across the lifespan.