Remote Delivery of a Mindfulness-Based Intervention for Adults with Tics: Protocol of a Randomized Controlled Trial

Abstract

Tourette Syndrome and persistent tic disorders (collectively, TS) are characterized by involuntary motor and/or vocal tics that onset in childhood. Existing evidence-based treatments—including behavior therapy and pharmacotherapy—are often only partially effective, associated with burdensome side effects, and/or inaccessible. The current paper describes a randomized controlled trial designed to compare a novel, remotely delivered mindfulness-based group intervention for tics (MBIT) to psychoeducation with relaxation and supportive therapy (PRST) in 150 adults with TS. All interventions and assessments will be delivered remotely using secure telehealth platforms and online electronic data capture systems. An independent evaluator masked to treatment condition will administer all tic assessments. The primary aims of the study are to: 1) examine the efficacy of MBIT relative to PRST for tic severity and 2) investigate the mechanism by which MBIT reduces tic severity. Additional aims include: 1) examination of secondary outcomes (e.g., comorbid conditions, quality of life), and 2) exploration of the durability of any observed improvements over a 6-month follow-up. Findings have the potential to meaningfully expand the range of evidence-based treatment options available to adults with TS.

1. Introduction

Tourette Syndrome and persistent tic disorders (collectively, TS) are characterized by involuntary motor and/or vocal tics that onset in childhood [1]. Individuals with TS also experience distressing somatosensory sensations (i.e., premonitory urges) and co-occurring mental health conditions such as anxiety disorders, depressive disorders, obsessive compulsive disorder (OCD), and attention deficit hyperactivity disorder (ADHD) [2, 3]. Tics and comorbid symptoms often cause significant distress and functional impairment [4, 5]. Consequently, many with TS experience a diminished quality of life [6]. Longitudinal studies reveal that tics persist into adulthood for at least 60% of individuals with TS [7].

Behavior therapy is the first-line treatment for TS [8, 9]. When compared to psychoeducation with supportive therapy in randomized clinical trials (RCTs), behavior therapy has proven safe and efficacious [10, 11]. Unfortunately, behavior therapy for adults with TS is often inaccessible [12, 13]. It is also ineffective for ~60% of the adults with TS who do access it, and provides minimal benefit for common co-occurring conditions [11, 14]. When behavior therapy is unavailable or insufficient for tic management, many adults with TS rely upon pharmacotherapy (e.g., antipsychotic medications) [15]. While efficacious, these medications often have adverse health consequences (e.g., diabetes, extrapyramidal symptoms, sedation, weight gain) that limit long-term tolerability [8, 16, 17]. Thus, there is a critical need for new treatments for adults with TS that are safe, efficacious, and accessible. In the trial described here, we aim to test whether an online mindfulness-based intervention for tics could address this need.

Mindfulness-based interventions (MBIs) promote the development of non-judgmental present moment awareness (i.e., mindfulness) through meditation, movement, discussion, and didactics. MBIs have demonstrated efficacy for a wide range of clinical conditions [18] with recent reports suggesting that they may also benefit adults with TS. Reese at al. [19] conducted an open trial of an eight-session, group-based, in-person modified form of Mindfulness-Based Stress Reduction [20] with 18 individuals with TS aged 16 or older. The intervention was feasible and acceptable with high retention and few adverse events—all of which were determined to be unrelated to the intervention. Participants experienced significant reductions in tic severity, tic-related impairment, and ~59% were deemed treatment responders, with therapeutic gains maintained at a 1-month follow-up. Given the importance of increasing access to care, a subsequent study [21] compared an online adaptation of this group-based intervention (termed Mindfulness-Based Intervention for Tics or MBIT) to Psychoeducation, Relaxation, and Supportive therapy (PRST) among 28 adults with TS. MBIT was feasible and acceptable with high retention and few adverse events—only three of which may have been related to the study interventions. MBIT produced significantly greater reductions in tic severity, and tic-related impairment than PRST. Notably, MBIT participants (69%) were more likely to exhibit a treatment response than PRST participants (13%) at post-treatment. Therapeutic gains achieved by MBIT participants were maintained at 6-month follow-up. Importantly, in contrast to traditional, in-person models of care, the online intervention delivery made the two treatments (MBIT and PRST) easily accessible to anyone with an internet connection and an electronic device—regardless of their geography.

Building from these promising findings, we describe the methods to rigorously test this novel intervention in a large RCT that compares MBIT to PRST among adults with TS. The two primary aims of this RCT are to examine the efficacy of MBIT relative to PRST for tic severity (Aim 1) and investigate the mechanism by which MBIT reduces tic severity (Aim 2). It will also examine the benefit of MBIT on secondary outcomes (e.g., comorbid conditions, quality of life) and explore the durability of any observed improvements.

2. Materials and Methods

2.1. Overview and design

This RCT will include 150 adults with TS who will be randomly assigned to receive either MBIT or PRST. Both interventions will consist of eight weekly 90-minute group sessions followed by three 60-minute booster sessions 2 weeks, 4 weeks and 8 weeks after acute treatment. Assessments will be conducted by Independent Evaluators (IEs) masked to treatment condition at screening, baseline, mid-treatment, post-treatment, and 1-month, 3-months, and 6-months post-treatment. All interventions and assessments will be delivered remotely using secure telehealth platforms (e.g., Zoom) and online electronic data capture systems (e.g. REDCap). The study has been reviewed and approved by the Johns Hopkins Medicine Institutional Review Board, is being overseen by a data and safety monitoring board, and has been pre-registered on clinicaltrials.gov (NCT06408662).

2.2. Participants

Participants must: (1) be ≥18 years of age; (2) meet diagnostic criteria for a primary or co-primary diagnosis of Tourette Syndrome or a Persistent Motor or Vocal Tic Disorder; (3) have moderate or greater tic severity as evidenced by a Yale Global Tic Severity Scale (YGTSS) Total Tic Score of >14 (when motor and vocal tics are present) or >10 (when only motor or vocal tics are present); (4) be medication free and/or on a stable dose of psychiatric medication eight weeks prior to participation; (5) not be engaged in psychotherapy for non-TS conditions and/or be on a stable course of therapy for six months prior to participation (6) be fluent in English; (7) have smart phone access to the mHealth app to monitor homework adherence and (8) live in a PSYPACT participating state within the US. Participants must also not have: (1) a current diagnosis of substance use disorder, psychosis, mania or another condition that requires more immediate care; (2) severe current suicidal/homicidal ideation and/or self-injury requiring intervention; (3) concurrent psychotherapy for TS; (4) prior extensive experience with mindfulness and/or meditation; (5) botox injection for TS within the past two months; (6) substantial evidence of inconsistent or unreliable reporting between Screen and Baseline visits.

2.3. Recruitment

In addition to recruiting participants through the Johns Hopkins Medicine / Kennedy Krieger Institute TS Center of Excellence, we will also recruit participants using outreach (e.g., letters, website postings, social media posts, email blasts, conference or meeting presentations) to state and regional chapters of the Tourette Association of America (TAA). We will also share information about the study with the TAA and other TS Centers of Excellence around the country. Finally, we will disseminate information about the study on internet pages designed specifically for the TS community (e.g., Reddit, Facebook).

2.4. Assessment tools and procedures

Participants will complete a Screening assessment to determine eligibility. Eligible participants will then be queued for treatment. Once the queue has enough participants to form a group (6–8 participants), the group will be scheduled for a Baseline assessment in the week prior to the intervention initiation (Week 0). The group will then be randomized in a 1:1 ratio to one of the study interventions according to a randomization schedule developed by the study statistician and participants will be told which intervention they will receive. Clinical outcomes will be assessed at Mid-treatment (Week 4–5), Post-treatment (Week 9), as well as 1-month (Week 12), 3-months (Week 21), and 6-months (Week 33) post-treatment. The schedule of assessments can be found in Table 1.

Table 1.

Assessment Schedule.

Measure	Construct	Outcome	Screen	Base-line	Mid-Tx	Post-Tx	1M-FU	3M-FU	6M-FU
DIAMOND	Psychiatric Diagnoses	Descriptive	X
D-TTHQ	Demographics/Treatment History	Descriptive	X
IE-MF	Treatment Condition Masking	Descriptive			X	X	X	X
YGTSS	Global Tic Severity	Primary	X	X	X	X	X	X	X
HM/VTS	Most Bothersome Tic Severity	Secondary		X	X	X	X	X	X
ATQ	Self-reported Tic Severity	Secondary		X	X	X	X	X	X
CGI-S / -I	Global Severity/Improvement	Secondary	X	X	X	X	X	X	X
WSAS	Tic-related Functional Impairment	Secondary		X		X		X
Y-BOCS-II	OCD Severity	Secondary		X	X	X	X	X	X
PHQ-9	Depression Severity	Secondary		X	X	X	X	X	X
ADHD-RS	ADHD Severity	Secondary		X	X	X	X	X	X
DASS	Depression, Anxiety & Stress	Secondary/Mechanistic		X	X	X	X	X	X
ARI/BITe	Irritability	Secondary		X	X	X	X	X	X
GAD-7	Anxiety Severity	Secondary		X	X	X	X	X	X
GTS-QOL	Quality of Life	Secondary		X		X		X
I-PUTS / PUTS	Premonitory Urge Severity	Mechanistic		X	X	X	X	X	X
MAIA-II	Interoceptive Awareness	Mechanistic		X	X	X	X	X	X
FFMQ	Mindfulness	Mechanistic		X	X	X	X	X	X
SCS	Self-Compassion	Mechanistic		X	X	X	X	X	X
ATTC	Attention Control	Mechanistic		X	X	X	X	X	X
NIMH ASQ	Suicidality	Safety	X	At Each Session			X	X	X
AEF	Adverse Event Monitoring	Safety		At Each Session			X	X	X
T/PRF	Idiographic Tic & Problem Ratings	Treatment		At Each Session
HRF	Skill Adherence / Utilization	Treatment		At Each Session
SSS	Therapeutic Adherence	Treatment		At Each Session
TEQ/CEQ	Treatment Credibility & Expectancy	Treatment			X1
PTR	Therapeutic Alliance	Treatment			X	X
CSQ-8	Acceptability & Satisfaction	Other				X		X	X

¹The TEQ/CEQ was administered between the first and second intervention session.

IEs masked to treatment condition will administer all clinician-rated assessments. IEs will receive specialized training on the administration of study instruments through a telehealth platform and pass initial reliability tests prior to conducting assessments. To ensure consistency and accuracy in ratings, IEs will receive weekly supervision from a Principal Investigator (JFM) and all assessments will also be recorded, with 20% randomly selected for review and co-rating. IEs will also complete the IE Masked Form (IE-MF) in which they will indicate their “best guess” for each participant’s treatment condition, level of certainty, and primary basis for the “guess”. This form has been used in prior clinical trials of TS to track the success or failure of IE masking [10, 11].

2.4.1. Diagnostic Assessment and Treatment History

The Diagnostic Interview for Anxiety, Mood and Obsessive-Compulsive and related Neuropsychiatric Disorders (DIAMOND) [22] is a clinician-rated interview to determine psychiatric disorder diagnoses and will be used to establish the TS diagnosis as well as any comorbid conditions. The DIAMOND has demonstrated excellent inter-rater reliability and validity [23]. The Demographic and Tic Treatment History Questionnaire (D-TTHQ) records demographic information as well as history of treatment for tics and related psychiatric symptoms and has been used in prior TS outcome studies [19, 24].

2.4.2. Tic-severity and tic-related impairment

The YGTSS [25, 26]), a clinician-rated measure of tic severity and tic impairment is considered the “gold standard” in RCTs. It has shown excellent reliability, validity, and treatment sensitivity [27, 28]. The YGTSS Total Tic Score (YGTSS-TTS) will serve as the primary outcome measure. The Clinical Global Impression of Severity (CGI-S) and Improvement (CGI-I) scales are clinician-rated measures that characterize global severity and improvement, respectively [29]. Historically, a rating of “Very Much Improved” or “Much Improved” on the CGI-I has been used to classify treatment response in TS clinical trials [10, 11].

Supplementing these global measures of tic severity, the severity of bothersome tics will be assessed using the Hopkins Motor/Vocal Tic Severity scale (HM/VTS), a clinician-rated measure that has shown good reliability, validity, and treatment sensitivity [30, 31]. Participants will also complete the Adult Tic Questionnaire (ATQ), a self-report measure of overall tic severity that has shown good reliability, validity, and treatment sensitivity [32].

2.4.3. Co-occurring psychiatric symptoms and quality of life.

The Yale-Brown Obsessive-Compulsive Severity Scale-Second Edition (Y-BOCS-II; [33]) is a clinician-rated measure of OCD severity that has shown good psychometric properties [33, 34]. The Attention Deficit Hyperactivity-Rating Scale (ADHD-RS; [35]) is a self-report measure of ADHD severity that has shown good psychometric properties. The Patient Health Questionnaire-9 item (PHQ-9; [36]) is a self-report measure of depression severity that has shown good psychometric properties and sensitivity to change among psychiatric patients [37]. The Depression, Anxiety, and Stress Scale (DASS; [38]) scale is a self-report measure that has shown good psychometric properties in clinical samples [39]. The Generalized Anxiety Disorder 7-item (GAD-7; [40]) is a self-report measure that has demonstrated adequate psychometric properties in a psychiatric sample [41]. The Affective Reactivity Index (ARI) and the Brief Irritability Test (BITe) are self-report measures of irritability that have shown good psychometric properties [42, 43].

The Work and Social Adjustment Scale (WSAS) is a self-report measure of functional impairment due to a specific disorder [44]. It has demonstrated good psychometric properties and has been used in prior TS studies [19, 21]. The Gilles de la Tourette Syndrome-Quality of Life (GTS-QOL; [45]) is a self-report measure of quality of life. It has shown good psychometric properties and been commonly used in TS studies [6, 46].

2.4.4. Theorized and Exploratory Treatment Mechanisms.

Theorized mechanisms of change include premonitory urge severity and psychosocial stress. Premonitory urge severity will be measured using the Individualized-Premonitory Urge to Tic Scale (I-PUTS [47]) and the Premonitory Urge to Tic Scale (PUTS [48]). The I-PUTS is a clinician-rated measure of the frequency and intensity of premonitory urge for each tic endorsed on the YGTSS. The PUTS is a self-report measure of global urge severity. These two scales have demonstrated excellent psychometric properties [47–49]. Psychosocial stress will be measured using the stress subscale of the DASS.

Exploratory mechanisms of change include interoceptive awareness, non-reactivity, and self-compassion. Interoceptive awareness will be measured using the Multidimensional Assessment of Interoceptive Awareness-2nd Edition (MAIA-2 [50]), a self-report measure that has demonstrated good reliability and validity [51]. Non-reactivity will be measured with the non-reactivity subscale of the Five Facet Mindfulness Questionnaire (FFMQ [52]). The FFMQ is a widely-used self-report measure of five aspects of mindfulness—observing, describing, acting with awareness, nonjudging of inner experience, and non-reactivity to inner experiences. It has good reliability, validity, and treatment sensitivity [53, 54]. Finally, self-compassion will be measured using the Self-Compassion Scale (SCS), a self-report measure that has demonstrated good reliability, validity, and treatment sensitivity [55, 56].

2.4.5. Safety and Adverse Event Monitoring.

Suicidal ideation and adverse events will be monitored throughout the trial. The IEs will administer the DIAMOND [22], which includes questions about suicidal ideation and behavior at Baseline. Additionally, participants will complete the NIMH Ask Suicide-Screening Questions (ASQ; [57]) to assess for emergent suicidal ideations and/or behaviors at each assessment visit and intervention session.

Adverse events will be monitored using a self-report Adverse Event Form (AEF) similar to that used in prior mindfulness for tics studies [21]. The AEF assesses events experienced by participants (e.g., worsening of mood, anxiety; physical injury, pain, tic exacerbation), the severity of such events, the perceived relatedness of the event to the intervention, and any treatment sought for the event. Given the subjectivity of participant’s severity ratings, the assessment team will review each reported adverse event and also rate severity using a standardized rating scale.

2.4.6. Treatment-related Measures and Forms.

Consistent with prior RCTs [11, 21], participants will complete ideographic self-report ratings of tic severity and related interference (Tic and Problem Rating Form (T/PRF) and self-reported skill utilization and homework adherence (HRF) at each session. The interventionist will also complete a Session Summary Sheet (SSS) for each participant after each session. The SSS includes a rating of attendance, participant’s perceived understanding of the therapeutic strategies, participant involvement in the session, a therapist rating of patient improvement, and any between-session contact between the interventionist and participant. The SSS was modeled after measures used in prior clinical trials of TS [10, 11].

The Treatment Expectations/Credibility Questionnaire (TEQ/CEQ) is a self-report measure of the credibility of the treatment rationale, and expectancy of change with good psychometric properties [58]. The Perception of Therapeutic Relationship (PTR) is a self-report measure of therapeutic alliance [59, 60] that has been used to assess therapeutic alliance in prior clinical trials of TS [10, 11]. The Client Satisfaction Questionnaire (CSQ-8 [61]) is a self-report measure assessing satisfaction with treatment that has demonstrated good reliability and validity [62, 63].

2.5. Interventions

Both study interventions consist of eight weekly, live, therapist-delivered 90-minute group meetings and between-session home practice. Three live, therapist-delivered 60-minute group booster sessions also occur at 2-, 4-, and 8 weeks post treatment. All sessions will be conducted over a secure telehealth platform. While both interventions are manualized and will follow detailed session agendas, participants will be provided with ample time for inquiry, discussion, and questions throughout. Therapists will flexibly respond to participant needs, as appropriate. Both interventions will be delivered by doctoral-level psychologists with extensive prior training and experience delivering online psychosocial interventions and MBIs, specifically.

2.5.1. Mindfulness-Based Intervention for Tics (MBIT)

MBIT consists of mindfulness and meditative practice, didactics, inquiry, discussion and between-session home practice. Because no prior mindfulness experience is assumed, participation begins with an introduction to mindfulness through foundational meditative practices (e.g., mindfulness of the senses, the body scan, mindfulness of the breath, body, thoughts, and emotions) and didactics (Sessions 1 & 2). These weeks of the program allow participants with practice developing capacities (e.g., attention regulation, body awareness, decentering, and distress tolerance) that can then be extended to working mindfully with premonitory urges and tics. This extension is facilitated through a series of “Riding the Wave” meditations that encourage awareness of premonitory urges and tics (Session 3), strategies for working with discomfort (Session 4), cultivation of a welcoming and kind stance toward premonitory urges and the self (Session 5), and finally, the adoption of a decentered stance towards premonitory urges that allows them to arise and subside without intervention (Session 6). Participants are encouraged to integrate mindfulness into daily life and use observations to make behavioral changes that reduce stress and promote ease (Session 7). Throughout the intervention, participants are provided with psychoeducation regarding tics and the theoretical model underlying this treatment approach. Towards the end of the intervention, participants are supported in consolidating their learning and becoming more independent in their mindfulness practice (Sessions 7 & 8). Booster sessions provide an opportunity to review study concepts and practices, identify current goals, and reconnect with group members. A fuller description of MBIT can also be found in Reese et al. [64].

2.5.2. Psychoeducation, Relaxation, and Supportive Therapy (PSRT)

PRST consists of psychoeducation, relaxation, discussion, and between-session homework. Each week, new psychoeducational content and/or therapeutic skills are introduced. Participants are given the opportunity to discuss the information and/or skills, and how they might apply them in their lives. Major topics include diagnosis, phenomenology, prevalence and course of TS (Session 1), etiology (Session 2), comorbid conditions and related concerns (Session 3), consequences of TS (Session 4), relaxation strategies (Session 5), healthy habits (Session 6), relationships and communication (Session 7), and self-esteem and joy (Session 8). Towards the end of treatment, participants are supported in consolidating learning and continuing to apply lessons learned to their lives. Booster sessions provide an opportunity to review study concepts and practices, identify current goals, and reconnect with group members.

2.5.3. Mobile Health (mHealth) application.

Both study interventions will include a mobile Health (mHealth) application. The HIPAA-compliant mHealth platform was developed to facilitate the dissemination and implementation of therapeutic skills and activities in evidence-based treatments [65]. Although initially created and tested to improve therapeutic skill adherence in patients with OCD, the platform’s functionality permits many other uses [66]. The platform (called OC-Go) consists of a web-based clinician portal and user-side mobile application that allows for asynchronous access to content. Once educational information and therapeutic activities are created by the treatment team, content becomes accessible to participants on mobile devices (e.g., smartphone, tablet computers). The asynchronous nature enables participants to engage with content and complete therapeutic activities in real-world settings in which therapeutic activities are most useful. Therapeutic activities incorporate multi-media content (e.g., text, infographics, audio, and/or video) to facilitate learning and promote understanding.

2.5.4. Intervention Fidelity monitoring

To assess and monitor intervention fidelity, all intervention sessions are video recorded and 20% randomly rated by a PI (HER) for protocol adherence and interventionist competence. The Mindfulness-Based Relapse Prevention Adherence and Competence Scale (MBRP-AC [67]) will be modified for this purpose. Adherence items will be created for every session of each intervention. MBIT competence items will closely follow the original MBRP-AC items, whereas those for PRST will be drawn from best practices for supportive therapy as outlined in prior TS RCTs [11]. The MBRP-AC has shown good psychometric properties. Ratings on this scale and areas identified for improvement will also be incorporated into weekly interventionist supervision.

2.6. Data analytic plan

Descriptive statistics (e.g., means and standard deviations, SDs) and graphical representations (e.g., histograms) will be generated for outcomes and covariates to ensure that data meet distributional and other assumptions for planned analyses. We will construct individual “sparkline” plots for each participant depicting tic severity, along with its putative mediators over time to determine the temporal ordering of improvements [68]. A low dropout rate is anticipated based on our pilot RCT (~3.5%) and we do not anticipate substantial participant attrition prior to the start of treatment. As a precaution, however, all primary analyses will be conducted under a modified intention to treat (ITT) principal—such that individuals who drop out prior to the receipt of any study intervention in their assigned arm will be excluded. This will ensure that efficacy analyses are conducted on participants with at least one post randomization visit in their assigned treatment condition, which is consistent with prior TS clinical trials [11]. As described in Jakobsen et al. [69], if there is more than 5% missing data, we will multiply impute missing data via chained equations [70]. All hypothesis tests will be two-sided with family-wise α set at 0.05. Thus, for Aim 2 we will use an α of 0.025 to account for there being two putative mediators being tested. Analyses for secondary and exploratory aims will not adjust for multiple comparisons.

For Primary Aim 1, we will compare the efficacy of MBIT to PRST for reducing tic severity on the YGTSS-TTS. We hypothesize that MBIT will result in greater reductions in tic severity compared to PRST at post-treatment. We will fit longitudinal linear mixed effect model [71] such that E[YGTSS-TTSij]=β0+β1MBIT+β2time+β3MBIT*time, with a random intercept for each individual and with adjustments for sex, age, and tic medication status. For the primary hypothesis we will consider change in YGTSS-TTS during the treatment period only (baseline, mid-treatment, post-treatment visits). We do not anticipate group effects within treatment arms, but we will fit additional models with random intercepts for individuals nested within random intercepts for group to determine if such effects occur.

For Primary Aim 2, we will evaluate the mechanisms by which MBIT reduces tic severity. Here, we hypothesize that MBIT will produce greater reductions in premonitory urge severity and stress compared to PRST. Accordingly, we will fit models analogous to those for Primary Aim 1 but use the I-PUTS, and the stress subscale of the DASS as outcomes. Next, we hypothesize that the magnitude by which MBIT improves tic severity will vary as a function of (i) improvements in premonitory urge severity and (ii) improvements in stress. We will fit models such that E[YGTSS-TTSij]=β0+β1ΔI-PUTS+β2time+ β3ΔI-PUTS *time. We will fit an analogous model for ΔDASS. We will also fit models with treatment arm assignment and corresponding interactions, including the 3-way interaction between the delta, time, and treatment arm, which would represent the difference in treatment response associated with a 1-unit difference in change over 8 weeks in either I-PUTS or DASS. We will also fit models with a 3-way interaction with sex to determine if sex as a biological variable is associated with differences in treatment effect. Guided by the sparkline plots described above, we will also fit a series of longitudinal lagged models where YGTSS-TTS at each timepoint is modeled as a function of putative mediators at the preceding timepoint and treatment arm.

For our secondary aim, we will examine the efficacy of MBIT for comorbid mental health symptoms and quality of life compared to PRST. We will fit mixed effects longitudinal linear models analogous to those described for Aim 1, but with additional outcomes for anxiety severity (GAD-7, DASS Anxiety subscale), ADHD severity (ADHD-RS), OCD severity (YBOCS-II), depression severity (PHQ-9, DASS depression subscale), and quality of life (GTS-QOL).

Finally, we will explore the durability of improvement from MBIT at the 6-month follow-up compared to PRST. We will examine the sustained therapeutic benefit of MBIT on tic severity, tic-related impairment, comorbid mental health symptoms (e.g., anxiety, ADHD, OCD, depression), and quality of life. We will fit ‘time-averaged’ mixed effects models to data from the post-treatment phase (post-treatment, 1M-FU, 3MFU) for all outcomes of interest. We will also compare 6-month follow-up scores to scores at post-treatment and baseline to determine what percentage of treatment effect remains.

3. Discussion

This RCT aims to examine the efficacy of MBIT, a novel, online, group intervention for adults with TS. Should MBIT prove efficacious in this large RCT, it would be the first new non-pharmacological, evidence-based treatment option for TS in almost 20 years. Notably, as MBIT is being delivered remotely via telehealth and in a group format, it would be the most widely accessible intervention of any kind for adults with TS. Taken together, the results of this trial, if positive, could meaningfully improve the treatment landscape for adults with TS.

This RCT will also provide new insights into mechanisms underlying MBIT by testing treatment mechanisms theorized within the neurobehavioral model of TS [72] and novel therapeutic mechanisms (i.e., interoceptive awareness, non-reactivity, self-compassion) that may be specific to MBIs. Given that there have been few prior studies examining mechanisms of change in TS [73, 74] these findings will meaningfully contribute to the literature and could be used to further refine and improve MBIT and other psychosocial interventions for TS.

Prior RCTs for TS have tended to narrowly focus on tic severity reduction. While tic severity reduction remains essential, this RCT intentionally was designed to also examine the interventions’ impact on comorbid conditions and quality of life. Based on our pilot work and prior literature demonstrating that MBIs can be beneficial for a broad range of psychological concerns [18], we expect that MBIT will result in improvements beyond tic reduction. By broadening our outcomes, we hope to better understand the degree to which MBIT can address common co-occurring concerns and improve quality of life—thereby treating the “whole person”.

Finally, we will use study findings to inform the development of a subsequent RCT testing the comparative effectiveness of MBIT relative to behavior therapy and evaluating moderators, mediators, and mechanisms of action in both approaches. We believe that this work would bring us closer to a personalized medicine approach to treatment selection for adults with TS.