Prevalence of tic disorders: a systematic review and meta-analysis

Polygenic and environmental determinants of tics in the Avon Longitudinal Study of Parents and Children

Tourette syndrome (TS) is caused by multiple genetic and environmental factors. Yet, little is known about the interplay of these factors in the occurrence of tics. We investigated whether polygenic risk score (PRS) of TS and pregnancy-related factors together enhance the explained variance of tic occurrence in the Avon Longitudinal Study of Parents and Children (N_cases  = 612; N_controls  = 4,201; 50% male; mean age 13.8 years). We included a cumulative adverse pregnancy risk score, maternal anxiety and depression, and maternal smoking and alcohol use during pregnancy. We investigated possible joint effects of genetic and pregnancy-related risk factors using a multivariable approach, and explored mediation effects between the pregnancy-related risk factors in explaining tic presence. The PRS and the cumulative adverse pregnancy risk score, maternal anxiety, or maternal depression explained significantly more variance of tic presence compared to models including only the PRS. Furthermore, we found that the cumulative adverse pregnancy risk score mediated the association between several pregnancy-related factors (maternal anxiety, depression, and smoking) and tics. The combination of a PRS and pregnancy-related risk factors explained more variance of tics in a general population cohort compared to studying these factors in isolation.

Systematic Review and Meta-Analysis of Tourette Syndrome Prevalence; 1986 to 2022

BACKGROUND

Tourette syndrome (TS) is a disorder characterized by a history of multiple motor tics and the emergence of at least one vocal tic during a period of the disorder. The current investigation sought to clarify the prevalence statistics for TS using a systematic review and meta-analysis.

METHODS

This systematic review and meta-analysis covered the period between 1986 and 2022. Embase, Scopus, PubMed, Web of Science, and Google Scholar were searched to locate articles pertinent to the study topic. The I² index was used to examine the heterogeneity of the studies, and a comprehensive meta-analysis was employed to analyze the data.

RESULTS

Ultimately, 30 studies (39 outcomes) were included in the meta-analysis and systematic review. The results showed the global prevalence of TS to be 0.5% (95% confidence interval [CI], 0.3% to 0.8%), with the highest rate of spread observed in the Americas at 0.6% (95% CI, 0.2% to 1.6 %). Analyzing the subgroups of the sample revealed that the highest prevalence was associated with the population of children and adolescents at 0.7% (95% CI, 0.4% to 1.4%) and males at 0.5% (95% CI, 0.2% to 1.0%).

CONCLUSIONS

This comprehensive review and meta-analysis revealed that the prevalence of TS worldwide is sufficiently high, such that attention of medical specialists and health policy makers is warranted.

The French version of the Gilles de la Tourette Syndrome Quality of Life Scale for adolescents (GTS-QOL-French-Ado): Adaptation and psychometric evaluation

INTRODUCTION

The aim of this study was to create a new version of the French GTS-QOL adapted to adolescents with GTS aged 12-16 years (GTS-QOL-French-Ado) and to evaluate its psychometric properties.

METHODS

We assessed the psychometric properties of the GTS-QOL-French-Ado in 84 adolescents (mean age 13.6 years, standard deviation 1.2) in terms of factor structure, internal consistency, reliability and convergent validity with the Child Depression Inventory (CDI), the Multidimensional Anxiety Scale for Children (MASC), the Motor tic, Obsessions and compulsions, Vocal tic Evaluation Survey (MOVES) and the French "Vécu et Santé Perçue de l'Adolescent" (VSP-A), a generic self-administered measure of health-related quality of life (HRQoL) in adolescents.

RESULTS

Exploratory factor analysis of the GTS-QOL-French-Ado resulted in a 5-factor solution. The GTS-QOL-French-Ado demonstrated good acceptability with missing values per subscale ranging from 0% to 1.2%, good internal consistency for four of the five subscales with Cronbach's alpha ranging from 0.56 to 0.87 and good test-retest reliability with intraclass correlation coefficients ranging from 0.74 (95% CI: 0.52-0.86) to 0.82 (95% CI: 0.66-0.91). Convergent validity was supported by correlations with CDI, MASC, MOVES, VSP-A and clinical variables.

DISCUSSION

The GTS-QOL-French-Ado is the first disease-specific HRQoL tool for French-speaking adolescents with GTS aged 12-16 years, and shows good psychometric properties. Further psychometric testing on responsiveness to change would be of great interest.

Trends of Tourette Syndrome in children from 2011 to 2021: A bibliometric analysis

Objective

Analyze the research status of Tourette Syndrome (TS) in children by CiteSpace and determine the current research hotspots and frontiers.

Materials and methods

We chose publications indexed in the Web of Science Core Collection (WoSCC) database for studies related to TS in children from 2011 to 2021. We built online cooperation maps of countries/regions, institutions, authors, journals, references, and keywords by CiteSpace, and identified hotspots and frontiers of study for children’s TS.

Results

A total of 1,232 publications about TS in children were downloaded from the WoSCC. The USA (414) was the country with the highest rate of production, and University College London (87) was the institution that had the highest publication rate. Andrea Eugenio Cavanna was the most prolific author (39 papers). There was inactive cooperation between institutions, countries/regions, and authors. The Journal of European Child & Adolescent Psychiatry was the most active journal. Hot topics focused on epidemiology, comorbidities, deep brain stimulation, behavioral therapy, basal ganglia, pharmacological treatment, and risk factors of TS in children.

Conclusion

According to the CiteSpace results, this study found that authors, countries/regions, and institutions were not actively working together. Current research hotspots mainly consist of epidemiology, comorbidities, deep brain stimulation, behavior therapy, and basal ganglia. The main research trends include comorbidities, pharmacological treatment, and risk factors. Therefore, international cooperation should be strengthened in the future, and it should be mindful of the psychiatric comorbidities of TS, the choice of intervention measures, and early warning of risk factors.

Neurodevelopmental disorders among Spanish school-age children: prevalence and sociodemographic correlates

BACKGROUND

Prevalence estimates of neurodevelopmental disorders (ND) are essential for treatment planning. However, epidemiological research has yielded highly variable rates across countries, including Spain. This study examined the prevalence and sociodemographic correlates of ND in a school sample of Spanish children and adolescents.

METHODS

The Child Behaviour Checklist/Teacher's Report Form/Youth Self-Report and the Conners' Rating Scales were administered for screening purposes. Additionally, teachers provided information on reading and writing difficulties. Subjects who screened positive were interviewed for diagnostic confirmation according to the Diagnostic and Statistical Manual of Mental Disorders criteria. The final population comprised 6834 students aged 5-17. Multivariate analyses were performed to determine the influence of gender, age, educational stage, school type, socioeconomic status (SES), and ethnicity on the prevalence estimates.

RESULTS

A total of 1249 (18.3%) subjects met criteria for at least one ND, although only 423 had already received a diagnosis. Specifically, the following prevalence rates were found: intellectual disabilities (ID), 0.63%; communication disorders, 1.05%; autism spectrum disorder (ASD), 0.70%; attention-deficit/hyperactivity disorder (ADHD), 9.92%; specific learning disorder (SLD), 10.0%; and motor disorders, 0.76%. Students of foreign origin and from low SES evidenced higher odds of having ID. Boys were more likely to display ASD or a motor disorder. Age, SES, and ethnicity were significant predictors for SLD, while communication disorders and ADHD were also associated with gender.

CONCLUSIONS

The prevalence of ND among Spanish students is consistent with international studies. However, a substantial proportion had never been previously diagnosed, which emphasise the need for early detection and intervention programmes.

Lifetime Prevalence, Predictors and Comorbidities of Tic Disorders: A Population-Based Survey of Children and Adolescents in Iran

In this population-based survey, we have evaluated the lifetime prevalence of tic disorders and related sociodemographic factors and comorbidities of them. The data obtained from face-to-face interviews with 29,885 children and adolescents aged 6-18 years. We used the multistage cluster sampling method and a cross-sectional design. Tic disorders and other psychiatric disorders were assessed using the Persian version of the Kiddie Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL). The lifetime prevalence of tic disorders was 1.5% (95% CI  (1.3-1.7%)). The highest prevalence was in the age range of 15-18 years old with 1.9% (95% CI  (1.6-2.3%)).57.7% (95% CI 51.8-63.3%) of patients with tic disorders had comorbidity with other psychiatric disorders. Increasing the prevalence of tic disorder with increasing age among Iranian children and adolescents, emphasizes the need to pay more attention to use of pharmacological and non-pharmacological treatments and increase education to families in this regard.

How do children with Tourette's syndrome and their caregivers live with the disorder? A systematic review of qualitative evidence

Background

Tourette's syndrome (TS) is a childhood neurodevelopmental disorder characterized by sudden, repetitive, involuntary, and irregular muscle movement and vocalization. Recently, non-pharmaceutical methods, such as behavioral therapy, psychotherapy, and deep brain stimulation, have been introduced as alternatives to pharmacological treatment for TS. This study aimed to systematically review and synthesize qualitative evidence on the experiences of children with TS and their caregivers. A meta-synthesis of qualitative evidence could help provide a comprehensive understanding of the challenges experienced by children with TS and their caregivers with the aim of providing more effective treatment and services for them.

Materials and methods

A systematic search was conducted using MEDLINE/PubMed, EMBASE, Cumulative Index to Nursing and Allied Health Literature, PsycARTICLES, and three Korean databases (Korean Medical Database, Research Information Sharing Service, and ScienceON) in July 2021. Studies were included if they collected and analyzed qualitative data from children with tic disorder or TS, or their caregivers. Qualitative research findings on the experiences and perspectives of children with TS and their caregivers were critically appraised and synthesized using the Joanna Briggs Institute methodology.

Results

Eight eligible studies were included. The findings from these studies (i.e., themes or subthemes of qualitative research) were aggregated into categories (a group of similar findings) and synthesized findings (a group of categorized findings). Ultimately, the 60 findings were aggregated into 15 categories. Finally, four synthesized findings were derived from the 15 categories: (i) continuation of challenging daily life, (ii) denying that TS causes emotional distress, (iii) accepting and understanding TS as part of oneself, and (iv) looking to the future.

Conclusion

Children with TS and their caregivers experience physical and psychological distress and social deprivation. Avoiding and suppressing TS causes secondary distress such as guilt. However, seeking social support and accepting the disorder reduce the distress caused by symptoms and lays the foundation for later growth. Even in the face of adversity, children with TS and their caregivers find personal value and acquire a more open and optimistic attitude toward life. This review shows that acceptance-based therapy and social support should be provided for the treatment and management of TS.

Estimating the number of people with Tourette syndrome and persistent tic disorder in the United States

Estimates of the number of people in the U.S. with Tourette syndrome or other persistent tic disorders can inform service provision planning. Based on available prevalence estimates applied to 2020 population data from the U.S. Census, we estimated that 350,000-450,000 U.S. children and adults have Tourette syndrome and about one million have other persistent tic disorders. Variation across studies makes estimating the total number of people in the United States affected by these disorders challenging. More precise measurement could ensure that prevalence estimates accurately reflect all who are impacted by these disorders and who could benefit from evidence-based services.

Incidence and prevalence of Tourette syndrome and chronic tic disorders in Taiwan: a nationwide population-based study

PURPOSE

The incidence of Tourette syndrome and chronic tic disorders has seldom been evaluated in Asia.

METHODS

Using the National Taiwan Insurance Research Database, the annual standardized incidence and prevalence of Tourette syndrome (TS) and chronic tic disorders were estimated from 2007 to 2015. The pre-existing comorbidity at disease diagnosis was also evaluated.

RESULTS

From 2007 to 2015, the age- and sex-standardized incidence increased from 5.34 (95% confidence interval [CI] 5.06-5.62) per 100,000 person-years to 6.87 (95% CI 6.53-7.21) per 100,000 person-years. In children and adolescents, the age- and sex-standardized incidence increased from 19.58 (95% CI 18.42-20.75) per 100,000 person-years to 31.79 (95% CI 30.09-33.49) per 100,000 person-years. In adults, the age- and sex-standardized incidence decreased from 2.01 (95% CI 1.79-2.23) per 100,000 person-years to 1.24 (95% CI 1.07-1.42) per 100,000 person-years. The incidence rate ratio (IRR) between males and females was 3.74 (95% CI 3.32-4.22). The age- and sex-standardized prevalence increased from 37.51 (95% CI 36.75-38.27) per 100,000 people in 2007 to 84.18 (95% CI 83.02-85.35) per 100,000 people in 2015. The rate risk (RR) between males and females was 3.65 (95% CI 3.53-3.78).

CONCLUSION

The annual incidence rates of TS and chronic tic disorders increased in childhood and adolescence but decreased in adulthood from 2007 to 2015. The prevalence rates increased over the same period.

Current and emerging pharmacotherapeutic strategies for Tourette syndrome

INTRODUCTION

Tourette syndrome (TS) is a chronic tic disorder characterized by both motor and vocal tics. The vast majority of patients present with co-morbid behavioral problems, especially tic-related obsessive-compulsive behaviors and attention-deficit and hyperactivity disorder. Evidence-based guidelines on the pharmacotherapy of TS have become available in recent years.

AREAS COVERED

The main purpose of this paper is to provide an overview of the current and emerging pharmacotherapeutic strategies for TS. A comprehensive search for the literature on the pharmacotherapy of tics was conducted using multiple databases (MEDLINE, Scopus, Web of Science, and Google Scholar), without date limits.

EXPERT OPINION

In consideration of the heterogeneity of the TS phenotypes, pharmacotherapy should be tailored to the individual patient. The choice of the pharmacological agent should take into account both the efficacy-to-tolerability ratio and the presence of co-morbid conditions. Evidence-based pharmacotherapy should aim at improving health-related quality life within a dynamic framework that typically requires active monitoring of the clinical presentation and reevaluation of the treatment intervention over time.

A Pilot Study on Plasma and Urine Neurotransmitter Levels in Children with Tic Disorders

Background: Tic disorders (TDs), including Tourette syndrome, are childhood-onset neuropsychiatric disorders characterized by motor and/or vocal tics that commonly affect children’s physical and mental health. The pathogenesis of TDs may be related to abnormal neurotransmitters in the cortico-striatal-thalamo-cortical circuitry, especially dopaminergic, glutamatergic, and serotonergic neurotransmitters. The purpose of this study was to preliminarily investigate the differences in the three types of neurotransmitters in plasma and urine between children with TD and healthy children. Methods: We collected 94 samples of plasma and 69 samples of urine from 3–12-year-old Chinese Han children with TD before treatment. The plasma and urine of the same number of healthy Chinese Han children, matched for age and sex, participating in a physical examination, were collected. Ultra-performance liquid chromatography-tandem mass spectrometry was used to detect the three types of neurotransmitters in the above samples. Results: The plasma levels of norepinephrine, glutamic acid, and γ-aminobutyric acid, and the urine levels of normetanephrine and 5-hydroxyindoleacetic acid were higher in the TD children than in healthy children. The area under the curve (AUC) values of the above neurotransmitters in plasma and urine analyzed by receiver operating characteristic curve analysis were all higher than 0.6, with significant differences. Among them, the combined AUC of dopamine, norepinephrine, normetanephrine, glutamic acid, and γ-aminobutyric acid in the 8–12-year-old subgroup was 0.930, and the sensitivity and specificity for TD were 0.821 and 0.974, respectively (p = 0.000). Conclusions: There are differences in plasma and urine neurotransmitters between TD children and healthy children, which lays a foundation for further research on the pathogenesis of TD.

Mechanisms of Action of Semen Ziziphi spinosae in the Treatment of Tourette Syndrome

Background

Semen Ziziphi spinosae, known as Suanzaoren (SZR) in Chinese, is a Chinese herbal medicine widely used in sedatives and tranquilizers. Although SZR is important for the clinical treatment of Tourette syndrome (TS), its mechanism of action remains unclear. Therefore, we investigated the pharmacological mechanisms of SZR in TS treatment using network pharmacology and systems biology approaches.

Methods

The bioactive components and potential targets of SZR were screened using the TCMSP database. UniProt was used to identify targets by mapping the known genes related to SZR. The known genes related to TS were identified by GeneCards and OMIM databases. A protein-protein interaction network was constructed using information from STRING 11.0 database. Cytoscape 3.8.0 software and Bioinformatics online platform were used for plotting this network. Gene ontology and KEGG enrichment analyses were performed using Metascape. Finally, AutoDock was used to verify the molecular docking.

Results

We found that SZR had 10 active compounds. There were 30 overlapping target genes between TS and SZR. These genes were associated with several signaling and metabolic pathways. AChE, SLC6A4, and HTR3A were the top three hub genes. The active components in SZR had a high binding affinity for the key targets.

Conclusion

SZR therapy for TS could achieve network regulation through the action of various active components of Chinese medicine on different targets and generate a complex regulatory relationship via interaction with potential targets, thereby playing a therapeutic role. Thus, SZR is a potential candidate for treating TS because it regulates nervous system functions.

Long-term efficacy, prognostic factors, and safety of deep brain stimulation in patients with refractory Tourette syndrome: A single center, single target, retrospective study

BACKGROUND

To evaluate the long-term efficacy, prognostic factors, and safety of posteroventral globus pallidus internus deep brain stimulation (DBS) in patients with refractory Tourette syndrome (RTS).

METHODS

This retrospective study recruited 61 patients with RTS who underwent posteroventral globus pallidus internus (GPi) DBS from January 2010 to December 2020 at the Chinese People's Liberation Army General Hospital. The Yale Global Tic Severity Scale (YGTSS), Yale-Brown Obsessive-Compulsive Scale (YBOCS), Beck Depression Inventory (BDI), Gilles de la Tourette Syndrome Quality-of-Life Scale (GTS-QOL) were used to evaluate the preoperative and postoperative clinical condition in all patients. Prognostic factors and adverse events following surgery were analyzed.

RESULTS

Patient follow up was conducted for an average of 73.33 ± 28.44 months. The final postoperative YGTSS (32.39 ± 22.34 vs 76.61 ± 17.07), YBOCS (11.26 ± 5.57 vs 18.31 ± 8.55), BDI (14.36 ± 8.16 vs 24.79 ± 11.03) and GTS-QOL (39.69 ± 18.29 vs 78.08 ± 14.52) scores at the end of the follow-up period were significantly lower than those before the surgery (p < 0.05). While age and the duration of follow-up were closely related to prognosis, the disease duration and gender were not. No serious adverse events were observed and only one patient exhibited symptomatic deterioration.

CONCLUSIONS

Posteroventral-GPI DBS provides long-term effectiveness, acceptable safety and can improve the quality of life in RTS patients. Moreover, DBS is more successful among younger patients and with longer treatment duration.

Effectiveness of 'Tackle Your Tics', a brief, intensive group-based exposure therapy programme for children with tic disorders: study protocol of a randomised controlled trial

INTRODUCTION

This paper outlines the study protocol for the Dutch Tackle Your Tics study in youth with tic disorders. Tourette syndrome and chronic tic disorders are prevalent neurodevelopmental disorders, placing considerable burden on youth and their families. Behavioural treatment is the first-line, evidence-based intervention for tic disorders, but tic reduction and availability remain relatively low. Patient associations stress the need for more accessible high-quality treatments, also focusing on improving quality of life. Therefore, the brief, intensive group-based treatment Tackle Your Tics was developed.

METHODS AND ANALYSIS

Tackle Your Tics is a 4-day intensive and comprehensive group-based intervention for children and adolescents (9-17 years) with Tourette syndrome or a chronic tic disorder. The programme encompasses exposure and response prevention treatment and additional supporting components (coping strategies, relaxation exercises and parent support). To study the effectiveness of Tackle Your Tics and identify predictors/moderators at baseline, a single-blinded randomised controlled trial (n=104) is conducted, comparing Tackle Your Tics (n=52) with a waiting list condition lasting 3 months (n=52). Assessments are performed at similar time points for both groups: at baseline, after 4 weeks, and at 3 and 6 months of follow-up, on tic severity, quality of life and other psychosocial variables.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the medical ethical committee of the Amsterdam Medical Centre (METC nr NL66340.018.18, v3 June 2020). Findings will be presented on national and international conferences, peer-reviewed scientific journals, patient organisation meetings and public media. Patient representatives are fully integrated as part of the research team. If Tackle Your Tics proves to be effective, it can expand evidence-based treatment possibilities for children and adolescents with tic disorders. Identifying the psychosocial predictors/moderators for the effectiveness of this intervention can provide personalised treatment advice in the future.

TRIAL REGISTRATION NUMBER

NL8052.

Neurosurgical management of Tourette syndrome: A literature review and analysis of a case series treated with deep brain stimulation

Tourette syndrome (TS) is a heterogeneous disorder, which clinical presentation includes both multiple motor and vocal tics and commonly associated psychiatric conditions (obsessive-compulsive disorder, attention deficit hyperactivity disorder, depression, anxiety, etc.). Treatment options primarily consist of non-pharmacological interventions (habit reversal training, relaxation techniques, cognitive behavioral therapy, and social rehabilitation) and pharmacotherapy. In case of the intractable forms, neurosurgical treatment may be considered, primarily deep brain stimulation (DBS). DBS appear to be effective in medically intractable TS patients, although, the preferential brain target is still not defined. The majority of studies describe small number of cases and the issues of appropriate patient selection and ethics remain to be clarified. In this article, we review the main points in management of TS, discuss possible indications and contraindications for neurosurgical treatment, and analyze our experience of DBS in a case series of refractory TS patients with the focus on target selection and individual outcomes.

Medication Choices in Children With Tic Disorders in Mainland China, Macao, Hong Kong, and Taiwan: Perspectives of Guardians and Physicians

Objective: Survey pediatricians and guardians of children with tic disorder on medication needs and choices.

Methods: We designed a cross-sectional survey for pediatricians in mainland China, Hong Kong, Macao, and Taiwan, as well as for the guardians of patients with tic disorder from West China Second University Hospital. We collected and analyzed information on clinicians’ medical behavior and medication choices and on guardians’ knowledge of tic disorder, medical treatment behaviors, and medication choices and needs.

Results: We collected responses from 242 physicians and 610 guardians. For patients with tic disorder and without comorbidities, the first-line drugs selected by physicians were tiapride (60.74%), clonidine (32.64%), haloperidol (25.62%), aripiprazole (16.53%), and sulpiride (12.4%). Physicians reported making medication choices by considerations such as clinical guidelines, clinical efficacy, a low incidence of adverse drug reactions, sufficient clinical research evidence, convenient dosage forms, and patient adherence. Guardians reported making medication choices by considerations such as a low incidence of adverse drug reactions, physician recommendations, clinical efficacy, dose, dosage forms, and the convenience and steadiness of obtaining the medication. However, guardians exhibited insufficient knowledge of tic disorder and treatment options.

Conclusions: Physicians and patient guardians differ in their considerations when selecting medications, highlighting a gap in optimizing treatment.

The Prevalence and Comorbidity of Tic Disorders and Obsessive-Compulsive Disorder in Chinese School Students Aged 6-16: A National Survey

Background: Obsessive-compulsive disorder (OCD) and tic disorders (TDs) are closely related and considered to etiologically overlap. Both disorders are characterized by repetitive behaviors. TD and OCD often co-occur. The high comorbidity between OCD and TD individuals suggests that we also need to pay more attention to the homogeneity and heterogeneity between TS and OCD. To date, there has been no systematic nationwide epidemiological survey of the mental health (including tic disorders and obsessive-compulsive disorder) of children and adolescents in China. Methods: A two-stage epidemiological study of psychiatric point prevalence was conducted. We used the multistage cluster stratified random sampling strategy to assess five provinces of China. The Child Behavior Checklist was used to identify behavioral problems among the enrolled students in the first stage. The results from the Mini-International Neuropsychiatric Interview for Children and Adolescents and evaluations from two psychiatrists based on the Diagnostic and Statistical Manual-IV were used to make a diagnosis. Point weighted prevalence for TD and OCD was estimated. We adjusted prevalence estimates with the product of sampling weights and poststratification weights. Standard error values and 95% confidential intervals were generated with Taylor series linearization. Rao−Scott adjusted chi-square (χ2) tests were employed to compare the prevalence estimates of different age and sex groups. Results: In the first stage, 73,992 participants aged 6−16 years old were selected. The prevalence rates of OCD and TDs were 1.37% (95% CI: 1.28−1.45) and 2.46% (95% CI: 2.35−2.57), respectively. The prevalence of OCD was found to be higher in girls (p < 0.001) and higher in boys with transient tic disorder (TTD) (p < 0.001) and Tourette’s syndrome (TS) (p < 0.001). The most common comorbidity of TS was OCD (40.73%), and for OCD, it was TS (11.36%). Conclusions: Our study is the first nationwide survey on the prevalence of TD (2.46%) and OCD (1.37%) in school students aged 6−16 years old in China. The high comorbidity between OCD and TD individuals suggested overlap based on the prevalence dimensions, which might be influenced by age and sex. This result suggested that we also need to pay more attention to the homogeneity and heterogeneity between TS and OCD.

Influence of sex on tic severity and psychiatric comorbidity profile in patients with pediatric tic disorder

AIM

To investigate sex-related differences in tic severity, tic-related impairments, and psychiatric comorbidities in childhood.

METHOD

In this cross-sectional study, tic severity/impairment and demographic factors were collected from 270 children and young people (aged 5-17y, mean 10y 6mo, SD 3y 4mo; 212 males and 58 females) with a tic disorder diagnosis at a specialty clinic. Psychiatric diagnoses and corresponding screening questionnaire scores were collected for attention-deficit/hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), major depressive disorder, and anxiety disorders. Logistic regression was used to compare the effect of sex and age on psychiatric comorbid diagnoses. The Mann-Whitney U test and t-tests were used to assess differences in questionnaire score distribution between sexes.

RESULTS

Females had more severe motor tics (12.55 vs 10.81, p=0.01) and higher global severity scores (38.79 vs 32.66, p=0.03) on the Yale Global Tic Severity Scale. Females were less likely to be diagnosed with ADHD (odds ratio=0.48, 95% confidence interval=0.26-0.89). No significant sex difference was observed in diagnosis rates or symptom severity scores for anxiety or OCD. Females had significantly higher scores than males on the Children's Depression Inventory, Second Edition.

INTERPRETATION

The higher level of motor tic severity and global severity in females further supports the differential natural history of tic disorders in females. Females with tic disorders may be underdiagnosed for ADHD.

Stimulant Induced Movement Disorders in Attention Deficit Hyperactivity Disorder

Stimulants, such as amphetamine and methylphenidate, are one of the most effective treatment modalities for attention deficit hyperactivity disorder (ADHD) and may cause various movement disorders. This review discusses various movement disorders related to stimulant use in the treatment of ADHD. We reviewed the current knowledge on various movement disorders that may be related to the therapeutic use of stimulants in patients with ADHD. Recent findings suggest that the use of stimulants and the onset/aggravation of tics are more likely to be coincidental. In rare cases, stimulants may cause stereotypies, chorea, and dyskinesia, in addition to tics. Some epidemiological studies have suggested that stimulants used for the treatment of ADHD may cause Parkinson’s disease (PD) after adulthood. However, there is still a lack of evidence that the use of stimulants in patients with ADHD may cause PD, and related studies are only in the early stages. As stimulants are one of the most commonly used medications in children and adolescents, close observations and studies are necessary to assess the effects of stimulants on various movement disorders, including tic disorders and Parkinson’s disease.

A prospective clinical cohort-based study of the prevalence of OCD, obsessive compulsive and related disorders, and tics in families of patients with OCD

BACKGROUND

The lifetime prevalence of obsessive - compulsive disorder (OCD) is currently estimated at 2 - 3% and the prevalence in first-degree family members is estimated to range between 10 and 11%. Separating OCD from other anxiety disorders and including it into the new "obsessive - compulsive and related disorders" (OCRDs) category has had a dramatic impact on the diagnosis, while also contributing to the better understanding of the genetics of these disorders. Indeed, grouping OCD with body dysmorphic disorder (BDD), and body-focused repetitive behaviors such as trichotillomania (hair pulling), onychophagia (nail biting), and excoriation (skin picking) into the same diagnostic family has resulted in a much greater lifetime prevalence (> 9%). These diagnostic changes necessitate an updated epidemiological study, thus motivating this investigation.

METHODS

The study sample comprised of 457 patient's cases from an Israeli and an Australian OCD center. Interviews were completed as a part of the intake or during treatment in each of the centers. Prevalence of OCD, OCRDs, tics, and other psychiatric comorbidities in first- and second-degree relatives was assessed by interviewing the OCD patients. Interviews were conducted by at least two researchers (LC, OBA, JZ) and only family information on which the interviewers have reached consensus was considered.

RESULTS

Initial analyses revealed an increase of OCD and OCRD prevalence in first- and second-degree family members as compared to the current literature due to reclassification of these disorders in DSM-5.

CONCLUSION

The new category of OCRD has changed the landscape of epidemiological studies in OCD. Further and broader studies are needed in order to better understand the lifetime prevalence of OCRD in first- and second-degrees family member.

Fecal transplantation can alleviate tic severity in a Tourette syndrome mouse model by modulating intestinal flora and promoting serotonin secretion

Background

: Tourette syndrome (TS) is a neuropsychiatric disorder with onset in childhood that warrants effective therapies. Gut microbiota can affect central physiology and function via the microbiota–gut-brain axis. Therefore, the gut microbiota plays an important role in some mental illnesses. A small clinical trial showed that fecal microbiota transplantation (FMT) may alleviate TS symptoms in children. Herein, FMT effects and mechanisms were explored in a TS mouse model.

Methods

: TS mice model (TSMO) (n = 80) were established with 3,3′-iminodipropionitrile, and 80 mice were used as controls. Mice were grouped into eight groups and were subjected to FMT with feces from children or mice with or without TS, or were given probiotics. Fecal specimens were collected 3 weeks after FMT. 16S rRNA sequencing, behavioral observation, and serum serotonin (5-HT) assay were performed. Differences between groups were analyzed using Mann-Whitney U test and Kolmogorov-Smirnov (KS) tests.

Results

: A total of 18 discriminative microbial signatures (linear discriminant analysis score > 3) that varied significantly between TS and healthy mice (CONH) were identified. A significant increase in Turicibacteraceae and Ruminococcaceae in TSMO after FMT was observed (P < 0.05). Compared with non-transplanted TSMO, the symptoms of those transplanted with feces from CONH were alleviated (W = 336, P = 0.046). In the probiotic and FMT experiments, the serum 5-HT levels significantly increased in TSMO that received probiotics (KS = 1.423, P = 0.035) and in those transplanted with feces from CONH (W = 336.5, P = 0.046) compared with TSMO without transplantation.

Conclusions

: This study suggests that FMT may ameliorate TS by promoting 5-HT secretion, and it provides new insights into the underlying mechanisms of FMT as a treatment for TS.

Cognitive control processes in behavior therapy for youth with Tourette's disorder

BACKGROUND

Cognitive control processes are implicated in the behavioral treatment of Tourette's disorder (TD). However, the influence of these processes on treatment outcomes has received minimal attention. This study examined whether cognitive control processes and/or tic suppression predicted reductions in tic severity and treatment response to behavior therapy.

METHOD

Fifty-three youth with TD or a pervasive tic disorder participated in a randomized wait list-controlled trial of behavior therapy. Following a baseline assessment to evaluate psychiatric diagnoses, tic severity, and cognitive control processes (e.g., response selection, inhibition, and suppression), youth were randomly assigned to receive eight sessions of behavior therapy (n = 23) or a wait list of equal duration (n = 28). Youth receiving immediate treatment completed a post-treatment assessment to determine improvement in tic severity. Meanwhile, youth in the wait list condition completed another assessment to re-evaluate tic severity and cognitive control processes, and subsequently received 8 sessions of behavior therapy followed by a post-treatment assessment to determine improvement.

RESULTS

A multiple linear regression model found that pretreatment inhibition/switching on the Delis-Kaplan Executive Function System Color-Word Interference Test predicted reductions in tic severity after behavior therapy (β = -.36, t = -2.35, p = .025, ƞ2  = .15). However, other cognitive control processes and tic suppression did not predict treatment response and/or reductions in tic severity. Small nonsignificant effects were observed in cognitive control processes after behavior therapy.

CONCLUSION

Cognitive control processes may influence tic severity reductions in behavior therapy. Notably, even when other cognitive control processes are impaired and youth are initially unable to voluntarily suppress their tics, youth with TD can still benefit from behavior therapy. Findings offer implications for clinical practice and research for TD.

Assessing the educational needs of physicians in the management of patients with Tourette syndrome: results of a United States survey on practicing clinicians and caregivers

Objective

To better understand current practices of U.S.-based physicians in the management of Tourette syndrome (TS) and identify gaps that may be addressed by future education.

Methods

Two survey instruments were developed to gather data on management of TS and perceptions from physicians and caregivers of children with TS. The clinician survey was developed in consultation with a TS physician expert and utilized clinical vignettes to assess and quantify practice patterns. The caregiver survey was adapted from the clinician survey and other published studies and gathered details on diagnosis, treatment, and perceptions regarding management.

Results

Data included responses from 138 neurologists (including 57 pediatric neurologists), 162 psychiatrists (including 42 pediatric psychiatrists), and 67 caregivers. Most (65%) pediatric neurologists rely solely on clinical findings to make a diagnosis, whereas the majority of other specialists utilize additional testing (eg, neuroimaging, lab testing, and genetics). Most psychiatrists (96%) utilize standardized criteria to make a diagnosis, whereas 22% of neurologists do not. Many physicians (44% of psychiatrists and 20% of neurologists) use pharmacotherapy to treat a patient with “slightly bothersome” tics and no functional impairment, whereas caregivers favored behavioral therapy. Most (76%) caregivers preferred to make the final treatment decision, whereas 80% of physicians preferred equal or physician-directed decision-making.

Conclusions

This study provides insight into practice patterns and perceptions of U.S.-based neurologists and psychiatrists in managing TS. Results highlight the potential value of physician education, including diagnostic approach, tic management and monitoring, involvement of caregivers in decision-making, and updates on TS management.

Allopregnanolone: The missing link to explain the effects of stress on tic exacerbation?

The neurosteroid allopregnanolone (3α-hydroxy-5α-pregnan-20-one; AP) elicits pleiotropic effects in the central nervous system, ranging from neuroprotective and anti-inflammatory functions to the regulation of mood and emotional responses. Several lines of research show that the brain rapidly produces AP in response to acute stress to reduce the allostatic load and enhance coping. These effects not only are likely mediated by GABA_A receptor activation but also result from the contributions of other mechanisms, such as the stimulation of membrane progesterone receptors. In keeping with this evidence, AP has been shown to exert rapid, potent antidepressant properties and has been recently approved for the therapy of moderate-to-severe postpartum depression. In addition to depression, emerging evidence points to the potential of AP as a therapy for other neuropsychiatric disorders, including anxiety, seizures, post-traumatic stress disorder and cognitive problems. Although this evidence has spurred interest in further therapeutic applications of AP, some investigations suggest that this neurosteroid may also be associated with adverse events in specific disorders. For example, our group has recently documented that AP increases tic-like manifestations in several animal models of tic disorders; furthermore, our results indicate that inhibiting AP synthesis and signalling reduces the exacerbation of tic severity associated with acute stress. Although the specific mechanisms of these effects remain partially elusive, our findings point to the possibility that the GABAergic activation by AP may also lead to disinhibitory effects, which could interfere with the ability of patients to suppress their tics. Future studies will be necessary to verify whether these mechanisms may apply to other externalising manifestations, such as impulse-control problems and manic symptoms.

Concordance and comorbidities among monozygotic twins with tic disorders

Gilles de la Tourette Syndrome (GTS) is a multifactorial neurodevelopmental disorder characterized by tics and multiple comorbidities. The pathophysiology is not yet fully understood, but both environmental and genetic risk factors seem to be involved. Twin studies provide important knowledge on genetic factors. We assessed the concordance of GTS and chronic tic disorders (CTD) in monozygotic (MZ) twins, and examined tic severity, symptoms of obsessive-compulsive disorder (OCD), attention deficit/hyperactivity disorder and autism spectrum disorder. Twin pairs, where at least one twin was diagnosed with any tic disorder, were identified through Danish Twin Registry, Psychiatric Central Registry, Danish National Patient Registry and National Tourette Clinic, Copenhagen University Hospital, Herlev. Zygosity was tested with single-nucleotide polymorphism (SNP) genotyping and clinical assessment was done with validated tools. 14 MZ twin pairs were included: five were discordant. Seven twin pairs were concordant for GTS, and for two pairs one twin had GTS and the other CTD. Among the twins with CTD or GTS, 50% had at least one comorbidity, which is higher than in background populations. The GTS + OCD-phenotype was significantly more frequent among GTS-concordant than among discordant twins. No statistically significant differences were found between the GTS-concordant and discordant twin pairs regarding tic severity or comorbidities. Thorough clinical assessment and SNP-based genotyping are important when conducting clinical twin studies. We found high concordance of GTS and CTD, which supports the notion that both disorders have common genetic risk factors. Further studies with larger cohorts including dizygotic twins are warranted for more conclusive results.

Changes of Cytokines in Children With Tic Disorder

Tic disorder (TD) is a common childhood-onset disease associated with abnormal development of brain networks involved in the motor and sensory processing. The underlying pathophysiological mechanisms in TD are still unclear. An involvement of immune mechanisms in its pathophysiology has been proposed. This study investigates the association between the changes of cytokines and the etiology and development of TD. Different expressions of cytokines in a larger number of samples in our study may provide new insights to the field. The levels of cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ) were evaluated in 1,724 patients who were clinically diagnosed with TD from 1 to 17.5 years old and 550 were from 6 months to 14.5 years old in the control group. We assessed the levels of cytokines according to the patient's medication status and the severity of the disease. Of the cytokines we investigated, the serum IL-6 concentration of children with TD was significantly higher than that of the control group, while the levels of other cytokines were lower in TD patients. In the patient group whose YTGSS score ranged from 1 to 9, the IL-4, IL-10, and IFN-γ levels increased in medication group compared to unmedication group. Our data suggested that the cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ) may play an important role in the etiology and the severity in TD. Whether drug intervention in the early stage of tic disorder has a better effect on children needs further research.

EEG Correlates of Active Stopping and Preparation for Stopping in Chronic Tic Disorder

Motor inhibition is an important cognitive process involved in tic suppression. As the right frontal lobe contains important inhibitory network nodes, we characterized right superior, middle, and inferior frontal gyral (RSFG, RMFG, RIFG) event-related oscillations during motor inhibition in youth with chronic tic disorders (CTD) versus controls. Fourteen children with CTD and 13 controls (10–17 years old) completed an anticipated-response stop signal task while dense-array electroencephalography was recorded. Between-group differences in spectral power changes (3–50 Hz) were explored after source localization and multiple comparisons correction. Two epochs within the stop signal task were studied: (1) preparatory phase early in the trial before motor execution/inhibition and (2) active inhibition phase after stop signal presentation. Correlation analyses between electrophysiologic data and clinical rating scales for tic, obsessive-compulsive symptoms, and inattention/hyperactivity were performed. There were no behavioral or electrophysiological differences during active stopping. During stop preparation, CTD participants showed greater event-related desynchronization (ERD) in the RSFG (γ-band), RMFG (β, γ-bands), and RIFG (θ, α, β, γ-bands). Higher RSFG γ-ERD correlated with lower tic severity (r = 0.66, p = 0.04). Our findings suggest RSFG γ-ERD may represent a mechanism that allows CTD patients to keep tics under control and achieve behavioral performance similar to peers.

Dopamine-2 receptor antibody encephalitis presenting as pure tongue-biting in a tourette syndrome patient: a case report

BACKGROUND

Tourette syndrome (TS) is a neuropsychiatric disorder characterized by repetitive and patterned tics. Its onset correlates with dysfunctions in immunological activation and neurotransmitters. Autoimmune movement disorders such as dopamine-2 receptor antibody encephalitis (D2R encephalitis) may go undiagnosed in TS patients seeking medical help for tic symptoms only. Here, we present a clinical case of D2R encephalitis in a TS patient.

CASE PRESENTATION

A 13-year-old boy with a history of TS presented with acute tongue-biting without positive neurologic examination or auxiliary examination results, except for a weakly positive finding for D2R antibodies in the serum sample. He was initially diagnosed with possible D2R encephalitis, but the influence of TS could not be ruled out. In addition to psychotropics, we administered immunotherapy early based on clinical characteristics, and his symptoms were ameliorated significantly. During the follow-up, he was diagnosed with definite D2R encephalitis, and the dosage of psychotropics was further adjusted for fluctuating symptoms.

CONCLUSIONS

Our case suggests that clinicians should discern D2R encephalitis in TS patients when tics are the primary symptoms. Administering immunotherapy early, according to clinical characteristics, may benefit the patient. Moreover, the features of premonitory urges could help evaluate the state of TS.

Lack of Association of FLT3 rs2504235 and Absence of SLITRK1 var321 in Patients with Tic Disorders from Guangdong Province, China

OBJECTIVE

Tic disorders (TDs) are highly polygenic and heritable neurodevelopmental disorders characterized by the presence of movements (motor tics) and/or vocalizations (phonic tics). SLITRK1 is a pathogenic variation of TD, and in a recent genome-wide association study in those of European ancestry, a single-nucleotide polymorphism (rs2504235) in the FLT3 gene was significantly associated with TDs/Tourette's syndrome. However, these results need to be proved in different populations. This study aimed to determine whether these two genetic variants were also associated with TD patients in south China.

METHODS

A total of 116 child TD patients and 114 healthy controls were included. All children underwent peripheral blood sampling for genomic DNA extraction. Gene fragments with two single-nucleotide polymorphisms were amplified by PCR and sequenced by Sanger chain termination before genotype analysis.

RESULTS

SLITRK1 var321 was not observed in any of the TD patients or controls. No significant difference was observed in allelic frequencies or genotypic distributions of rs2504235 between TD patients and controls.

CONCLUSION

Our results provide no evidence to support the previous conclusion that SLITRK1 var321 plays a major role in TDs, and FLT3 rs2504235 was not significantly associated with TDs in our cohort.

Digital and remote behavioral therapies for treating tic disorders: Recent advances and next steps

The rapid expansion of access to and engagement with digital technology over the past 15 years has transformed the potential for remote delivery of evidence-based digital health interventions (DHIs). Digital and remote behavioral interventions have the potential to address current gaps in the provision of evidence-based therapies in healthcare services. As the lack of access to behavioral treatments for people with tic disorders is a pressing issue across the world, there is great potential for DHIs to close this treatment gap. Here, we present a critical synthesis of the recent key advances in the field of digitally delivered, remote therapy for tics, outlining the research evidence for the clinical and cost-effectiveness and acceptability of digital or remotely delivered therapy. We found five trials aimed at reducing tic severity in children and young people and one trial for adults. The evidence supports the clinical utility of DHIs to deliver tic therapies, which shows promise in being clinically efficacious compared to an active control. Furthermore, DHIs in trials show good adherence and engagement and are acceptable to patients. The role of human support (including therapists and parents for young people) is likely to be important to encourage adherence. DHIs, where the main therapeutic content is delivered via web-based chapters, are likely to reduce clinical time, and maintain intervention fidelity, but further research is required to understand cost-effectiveness. Despite utilizing randomized controlled trials, only two trials were sufficiently powered to address efficacy and only one trial explored contextual factors that may influence engagement. Moreover, only one trial followed patients for >12 months, thus further long-term follow-ups are required. Specifically, we note that despite an emerging evidence base, DHIs for tics are yet to be routinely implemented in healthcare provision in any country. Drawing on the existing evidence, we conclude by proposing a stepped care model, in which digital therapy is implemented as a widely accessible first-line treatment using a purely online or therapist-supported approach.

Hair cortisol-a stress marker in children and adolescents with chronic tic disorders? A large European cross-sectional study

BACKGROUND

There is clear evidence that tic disorders (TDs) are associated with psychosocial stress as well as emotional and behavioral problems. Studies have shown that individuals with TDs have higher acute physiological stress responses to external, single stressors (as reflected by saliva cortisol). The aim of the present study was to examine a physiological marker of longer-term stress (as reflected by hair cortisol concentration) in children and adolescents with TDs and unaffected siblings of individuals with TDs.

METHODS

Two samples of a European cohort were included in this study. In the COURSE sample, 412 children and adolescents aged 3-16 years with a chronic TD including Tourette syndrome according to DSM IV-TR criteria were included. The ONSET sample included 131 3-10 years old siblings of individuals with TDs, who themselves had no tics. Differences in hair cortisol concentration (HCC) between the two samples were examined. Within the COURSE sample, relations of HCC with tic severity and perceived psychosocial stress as well as potential effects and interaction effects of comorbid emotional and behavioral problems and psychotropic medication on HCC were investigated.

RESULTS

There were no differences in HCC between the two samples. In participants with TDs, there were no associations between HCC and tic severity or perceived psychosocial stress. No main effects of sex, psychotropic medication status and comorbid emotional and behavioral problems on HCC were found in participants with TDs.

CONCLUSION

A link between HCC and TDs is not supported by the present results.

Bullying Victimization and Perpetration Among US Children with and Without Tourette Syndrome

OBJECTIVE

Tourette syndrome (TS) and co-occurring mental, behavioral, and developmental disorders (MBDDs) have been shown to affect peer relationships. This study provides nationally representative estimates of diagnosed TS prevalence and the prevalence of parent-reported bullying victimization and perpetration among US children with and without TS.

METHODS

This study included 2016-2017 National Survey of Children's Health data on children aged 6 to 17 years (N = 51,001) with parent-reported responses about TS diagnosis and their child's experiences with bullying victimization and perpetration. We calculated weighted prevalence estimates of diagnosed TS and of bullying indicators among children ever diagnosed with TS compared with peers without TS. We conducted a logistic regression analysis to estimate adjusted prevalence ratios of bullying involvement by TS status, controlling for age, sex, and co-occurring MBDDs.

RESULTS

By parent report, 0.3% of US children had ever received a diagnosis of TS; most children with a TS diagnosis (83.2%) had a co-occurring MBDD. Among children with TS, 56.1% experienced bullying victimization, 20.7% experienced bullying perpetration, and 15.9% experienced both, compared with 21.6%, 6.0%, and 4.1% for children without TS, respectively. After adjusting for age, sex, and co-occurring MBDDs, only the association between TS and bullying victimization remained statistically significant.

CONCLUSION

Compared with children without TS, children with TS overall experience more bullying victimization and perpetration. Health care professionals treating children with TS could assess challenges with peer relationships and co-occurring disorders to provide targeted support and referral.

Open-case series of a remote administration and group setting comprehensive behavioral intervention for tics (RG-CBIT): A pilot trial

PURPOSE

The comprehensive behavioral intervention for tics (CBIT) is the first-line psychotherapeutic treatment for individuals with tic disorders. However, most patients with tic disorders do not have access to CBIT due to different factors including lack of trained therapists, treatment cost, and travel distance. Such barriers are more prominent in non-English speaking countries. Therefore, the current study assessed the preliminary efficacy, feasibility, and acceptability of remotely administered group CBIT (RG-CBIT) in Japan.

METHODS

This was an open-case series that adopted the AB design. Three Japanese children aged between 6 and 13 years who were diagnosed with TS were recruited. RG-CBIT was developed based on the published CBIT manual. Videoconference application, slide presentation software, and cloud learning platform were used as appropriate.

RESULTS

The Yale Global Tic Severity Scale scores of all participants decreased from baseline to post-treatment. That is, the score reduced by an average of 7.0. Regarding feasibility and acceptability, the attendance rate of participants was 100%, and the process measurement items had favorable scores.

CONCLUSIONS

RG-CBIT had satisfactory efficacy, feasibility, and acceptability. Hence, it could mitigate the barriers for treatment access.

Vitamin D levels in children and adolescents with chronic tic disorders: a multicentre study

This study investigated whether vitamin D is associated with the presence or severity of chronic tic disorders and their psychiatric comorbidities. This cross-sectional study compared serum 25-hydroxyvitamin D [25(OH)D] (ng/ml) levels among three groups: children and adolescents (3-16 years) with CTD (n = 327); first-degree relatives (3-10 years) of individuals with CTD who were assessed for a period of up to 7 years for possible onset of tics and developed tics within this period (n = 31); and first-degree relatives who did not develop tics and were ≥ 10 years old at their last assessment (n = 93). The relationship between 25(OH)D and the presence and severity of tics, as well as comorbid obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD), were analysed controlling for age, sex, season, centre, latitude, family relatedness, and comorbidities. When comparing the CTD cohort to the unaffected cohort, the observed result was contrary to the one expected: a 10 ng/ml increase in 25(OH)D was associated with higher odds of having CTD (OR 2.08, 95% CI 1.27-3.42, p < 0.01). There was no association between 25(OH)D and tic severity. However, a 10 ng/ml increase in 25(OH)D was associated with lower odds of having comorbid ADHD within the CTD cohort (OR 0.55, 95% CI 0.36-0.84, p = 0.01) and was inversely associated with ADHD symptom severity (β = - 2.52, 95% CI - 4.16-0.88, p < 0.01). In conclusion, lower vitamin D levels were not associated with a higher presence or severity of tics but were associated with the presence and severity of comorbid ADHD in children and adolescents with CTD.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part I: assessment

In 2011 a working group of the European Society for the Study of Tourette Syndrome (ESSTS) has developed the first European assessment guidelines for Tourette syndrome (TS). Now, we present an updated version 2.0 of these European clinical guidelines for Tourette syndrome and other tic disorders, part I: assessment. Therefore, the available literature has been thoroughly screened, supplemented with national guidelines across countries and discussions among ESSTS experts. Diagnostic changes between DSM-IV and DSM-5 classifications were taken into account and new information has been added regarding differential diagnoses, with an emphasis on functional movement disorders in both children and adults. Further, recommendations regarding rating scales to evaluate tics, comorbidities, and neuropsychological status are provided. Finally, results from a recently performed survey among ESSTS members on assessment in TS are described. We acknowledge that the Yale Global Tic Severity Scale (YGTSS) is still the gold standard for assessing tics. Recommendations are provided for scales for the assessment of tics and psychiatric comorbidities in patients with TS not only in routine clinical practice, but also in the context of clinical research. Furthermore, assessments supporting the differential diagnosis process are given as well as tests to analyse cognitive abilities, emotional functions and motor skills.

Mycoplasma pneumoniae IgG positivity is associated with tic severity in chronic tic disorders

Infectious pathogens may represent an environmental risk factor for chronic tic disorders (CTD). This cross-sectional study aimed to determine whether Mycoplasma pneumoniae (M. pneumoniae) IgG positivity is associated with the presence or severity of tics. We compared M. pneumoniae IgG positivity across three groups: children and adolescents (3-16 years) with CTD (CTD group; n = 302); siblings (3-10 years) of people with CTD who developed tics within a seven-year follow-up period (tic onset group; n = 51); siblings (4-10 years) who did not develop tics within the study period and were ≥10-years-old at their last assessment (unaffected group; n = 88). The relationship between M. pneumoniae IgG positivity and the presence and severity of tics was analysed using multilevel models controlling for site, family relatedness, sex, age, presence of comorbid obsessive-compulsive and/or attention-deficit/hyperactivity disorder and use of psychotropic medication. M. pneumoniae IgG positivity was not associated with the presence of CTD, or the first onset of tics as compared to siblings who remained unaffected. M. pneumoniae IgG positivity was associated with a higher tic severity score within the CTD group (β = 2.64, s.e. = 1.15, p = 0.02). It is possible that M. pneumoniae infection influences tic severity in CTD or, that having more severe tics, increases the risk of infection. However, it is more likely that the association observed in this study reflects a propensity toward enhanced immune responses in people with CTD and that, rather than a causal relationship, infection and greater tic severity are indirectly linked via shared underlying immune mechanisms.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part IV: deep brain stimulation

In 2011 the European Society for the Study of Tourette Syndrome (ESSTS) published its first European clinical guidelines for the treatment of Tourette Syndrome (TS) with part IV on deep brain stimulation (DBS). Here, we present a revised version of these guidelines with updated recommendations based on the current literature covering the last decade as well as a survey among ESSTS experts. Currently, data from the International Tourette DBS Registry and Database, two meta-analyses, and eight randomized controlled trials (RCTs) are available. Interpretation of outcomes is limited by small sample sizes and short follow-up periods. Compared to open uncontrolled case studies, RCTs report less favorable outcomes with conflicting results. This could be related to several different aspects including methodological issues, but also substantial placebo effects. These guidelines, therefore, not only present currently available data from open and controlled studies, but also include expert knowledge. Although the overall database has increased in size since 2011, definite conclusions regarding the efficacy and tolerability of DBS in TS are still open to debate. Therefore, we continue to consider DBS for TS as an experimental treatment that should be used only in carefully selected, severely affected and otherwise treatment-resistant patients.

Targeted Interventions in Tourette's using Advanced Neuroimaging and Stimulation (TITANS): study protocol for a double-blind, randomised controlled trial of transcranial magnetic stimulation (TMS) to the supplementary motor area in children with Tourette's syndrome

INTRODUCTION

Tourette's syndrome (TS) affects approximately 1% of children. This study will determine the efficacy and safety of paired comprehensive behavioural intervention for tics (CBIT) plus repetitive transcranial magnetic stimulation (rTMS) treatment in children with Tourette's syndrome. We hypothesise that CBIT and active rTMS to the supplementary motor area (SMA) will (1) decrease tic severity, and (2) be associated with changes indicative of enhanced neuroplasticity (eg, changes in in vivo metabolite concentrations and TMS neurophysiology measures).

METHODS AND ANALYSIS

This study will recruit 50 youth with TS, aged 6-18 for a phase II, double-blind, block randomised, sham-controlled trial comparing active rTMS plus CBIT to sham rTMS plus CBIT in a 1:1 ratio. The CBIT protocol is eight sessions over 10 weeks, once a week for 6 weeks and then biweekly. The rTMS protocol is 20 sessions of functional MRI-guided, low-frequency (1 Hz) rTMS targeted to the bilateral SMA over 5 weeks (weeks 2-6). MRI, clinical and motor assessments and neurophysiological evaluations including motor mapping will be performed 1 week before CBIT start, 1 week after rTMS treatment and 1 week after CBIT completion. The primary outcome measure is Tourette's symptom change from baseline to post-CBIT treatment, as measured by the Yale Global Tic Severity Scale. Secondary outcomes include changes in imaging, neurophysiological and behavioural markers.

ETHICS AND DISSEMINATION

Ethical approval by the Conjoint Health Research Ethics Board (REB18-0220). The results of this study will be published in peer-reviewed scientific journals, on ClinicalTrials.gov and shared with the Tourette and OCD Alberta Network. The results will also be disseminated through the Alberta Addictions and Mental Health Research Hub.

TRIAL REGISTRATION

NCT03844919.

The effectiveness of Chinese herbal medicine for tic disorders in children and adolescents: A protocol for systematic review and meta analysis

BACKGROUND

The tic disorders are common neuropsychiatric disorders that affects the growth and development of children and adolescents. Chinese herbal medicine is commonly used for the treatment of tic disorders. However, there is no consensus on the difference in clinical efficacy compared with routine treatment. Therefore, we plan to perform a systematic review and meta-analysis to review the clinical efficacy of Chinese herbal medicine for tic disorders.

METHODS

Cochrane Central Register of Controlled Trials, PubMed, EMBASE, Chinese National Knowledge Infrastructure, Chinese Bio-medical Database, and Wanfang database will be searched from their inception until March 31, 2021. The meta-analysis will be conducted with Review Manager 5.3 software to systematically review the clinical efficacy and safety of Chinese herbal medicine for tic disorders. The primary outcome will include the improvement rate (amount) of tic symptoms using related scales or methods, and the secondary outcome will include adverse events.

RESULTS

This analysis will provide useful information about clinical efficacy and safety of Chinese herbal medicine for tic disorders.

CONCLUSIONS

Our study will generate strong evidence of Chinese herbal medicine for patients with tic disorders and provide suggestions for clinical practice.

The relationship between allergic diseases and tic disorders: A systematic review and meta-analysis

This systematic review aims to 1) explore the association between tic disorders (TD) and allergic diseases (AD), 2) judge whether patients with a diagnosis of TD are prone to suffer from a specific AD, by compiling the literature and analyzing the evidence. A literature search was conducted in PubMed and Embase database on February 24, 2021. The inclusion criteria for the literature were all comparative studies that reported TD patients were diagnosed with allergic illness as well. We identified that TD is positively associated with asthma, allergic rhinitis and allergic conjunctivitis, respectively. Especially, provisional tic disorder (PTD) patients might be more likely to suffer from these three AD, although it is still difficult to accurately predict which specific AD is prone to be accompanied by a specific TD. Shared genetic and etiological factors are suggested responsible for the AD-TD association. Large prospective cohort studies in future might shed light on a deep understanding of the relationship between immune disorders and tics.

Is Tourette syndrome a rare condition?

Based on its prevalence, Tourette syndrome cannot be considered a rare condition. However, in this opinion article, we make the claim that it should nonetheless be considered as an orphan or neglected disease.

Comorbidities in Obsessive-Compulsive Disorder Across the Lifespan: A Systematic Review and Meta-Analysis

Comorbidities are seen with obsessive-compulsive disorder (OCD) across the lifespan. Neurodevelopmental comorbidities are common in young children, followed by mood, anxiety, and obsessive-compulsive related disorders (OCRDs) in children, adolescents and adults, and neurological and degenerative disorders in the elderly. Understanding comorbidity prevalence and patterns has clinical and research implications. We conducted a systematic review and meta-analysis on comorbidities in OCD across the lifespan, with the objective to, first, estimate age-wise pattern and prevalence of comorbidities with OCD and, second, to examine associations of demographic (age at assessment, gender distribution) and clinical characteristics (age of onset, illness severity) with comorbidities. Four electronic databases (PubMed, EMBASE, SCOPUS, and PsycINFO) were searched using predefined search terms for articles published between 1979 and 2020. Eligible studies, across age, reported original findings on comorbidities and had an OCD sample size of ≥100. We excluded studies that did not use standardised diagnostic assessments, or that excluded patients on the basis of comorbidity. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The review protocol has been registered on the International Prospective Register of Systematic Reviews. A comorbidity rate of 69% was found in a pooled sample of more than 15,000 individuals. Mood disorders (major depressive disorder), anxiety disorders (generalised anxiety disorder), neurodevelopmental disorders (NDDs) and OCRDs were the commonest comorbidities. Anxiety disorders prevailed in children, mood disorders in adults, whereas NDDs were similarly prevalent. Higher comorbidity with any psychiatric illness, NDDs, and severe mental disorders was seen in males, vs. females. Illness severity was inversely associated with rates for panic disorder, tic disorders, OCRDs, obsessive compulsive personality disorder, and anorexia nervosa. This systematic review and meta-analysis provides base rates for comorbidities in OCD across the lifespan. This has implications for comprehensive clinical evaluation and management planning. The high variability in comorbidity rates suggests the need for quality, multi-centric, large studies, using prospective designs. Systematic Review Registration: Unique Identifier: CRD42020215904.

Clinical Practice Patterns in Tic Disorders Among Movement Disorder Society Members

Background

Tic disorders belong to the broad spectrum of pediatric and adult movement disorders. The wide variability in clinical presentations, applied assessment tools, and treatments are poorly understood.

Objectives

To map practices and knowledge base of movement disorder clinicians concerning clinical features, pathophysiology, and treatment approaches in tic disorders.

Methods

A 33-item survey was developed by the Tic Disorders and Tourette syndrome Study Group members of the Movement Disorder Society. The survey was distributed to the complete society membership and included responses from 346 members, 314 of whom reported treating tic disorders.

Results

Approximately one third of survey respondents (35%) frequently evaluated patients with tics. The data revealed widespread use of existing guidelines (about 70%) and screening for comorbid disorders (>90%). The most common investigations used to rule out secondary causes of tics were imaging (92%), laboratory tests (66%) and neurophysiology (38%). Functional tics were the second most common tic etiology following primary tics. Only 27% of respondents reported confidence in knowledge about tic pathogenesis. Top rated interventions to treat tics were psychoeducation, cognitive behavioral intervention for tics (CBIT) and treatment for neuropsychiatric comorbidities. Antipsychotics were ranked as the most effective pharmacologic tic intervention.

Conclusions

The majority of movement disorders specialists do not frequently encounter tics. There was sparse knowledge about tic pathophysiology. Psychoeducation, CBIT, the treatment of neuropsychiatric comorbidities and use of antipsychotics emerged as the most common interventions to treat tics. These results provide insight into what will be needed to improve the diagnosis and treatment of tic disorders.

Genetic architecture of Tourette syndrome: our current understanding

Tourette syndrome (TS) is a severe neuropsychiatric disorder characterized by recurrent, involuntary physical and verbal tics. With a prevalence as high as 1% in children, a deeper understanding of the etiology of the disorder and contributions to risk is critical. Here, we cover the current body of knowledge in scientific literature regarding the genetics of TS. We first review the history and diagnostic criteria for TS cases. We then cover the prevalence, and begin to address the etiology of the disorder. We highlight long-standing evidence for a genetic contribution to TS risk from epidemiology studies focused on twins, families, and population-scale data. Finally, we summarize current large-scale genetic studies of TS along specific classes of genetic variation, including common variation, rare copy number variation, and de novo variation that impact protein-coding sequence. Although these variants do not account for the entirety of TS genetic risk, current evidence is clear that each class of variation is a factor in the overall risk architecture across TS cases.

Recent progress on Tourette syndrome

Tic disorders and Tourette syndrome are the most common movement disorders in children and are characterized by movements or vocalizations. Clinically, Tourette syndrome is frequently associated with comorbid psychiatric symptoms. Although dysfunction of cortical–striatal–thalamic–cortical circuits with aberrant neurotransmitter function has been considered the proximate cause of tics, the mechanism underlying this association is unclear. Recently, many studies have been conducted to elucidate the epidemiology, clinical course, comorbid symptoms, and pathophysiology of tic disorders by using laboratory studies, neuroimaging, electrophysiological testing, environmental exposure, and genetic testing. In addition, many researchers have focused on treatment for tics, including behavioral therapy, pharmacological treatment, and surgical treatment. Here, we provide an overview of recent progress on Tourette syndrome.

Prevalence of Ophthalmic Manifestations Related to Tourette Syndrome Based on Big Data

Purpose: To investigate the prevalence of ophthalmic manifestations in patients with Tourette syndrome using big data based on samples extracted from the Health Insurance Review and Assessment Service. Methods: The study participants included Korean patients under the age of 18 years who had received a Tourette syndrome diagnostic code (F95.2) between January 1, 2012, and December 31, 2016. Ophthalmic manifestations reported to be related to Tourette syndrome such as tic disorder, blepharospasm, involuntary gaze abnormality, and strabismus were selected as ophthalmic clinical diagnostic codes; amblyopia and refractive errors that had never been investigated in conjunction with Tourette syndrome were also selected. Prevalence was investigated using big data. Results: A total of 3,643 Tourette syndrome patients (2,777 men and 866 women) were included in the study. The number of patients receiving a tic disorder diagnostic code was 3,643 (100%); blepharospasm, 48 (1.3%); involuntary gaze abnormalities, 9 (0.2%); and strabismus, 109 (3%). In addition, the number of patients receiving an amblyopia diagnostic code was 29 (0.8%), and the number of patients with a refractive errors code was 1,306 (35.8%). Conclusions: Tourette syndrome can be accompanied by several ophthalmic manifestations. Thus, cooperation between a neuropsychiatrist and an ophthalmologist, and regular ophthalmological examinations, are considered necessary.

WISC-IV performance of children with Chronic Tic Disorder, Obsessive-Compulsive Disorder and Attention-Deficit/Hyperactivity Disorder: results from a German clinical study

BACKGROUND

Chronic Tic Disorder (CTD), Obsessive-Compulsive Disorder (OCD) and Attention-Deficit/Hyperactivity Disorder (ADHD) are complex neuropsychiatric disorders that frequently co-occur. The aim of this study was to examine WISC-IV performance of a clinical cohort of children with CTD, OCD and/or ADHD.

METHODS

N = 185 children aged 6 to 17 years from Germany with CTD, OCD and/or ADHD were examined with the WISC-IV that comprises four index scores (VCI: Verbal Comprehension Index, PRI: Perceptual Reasoning Index, WMI: Working Memory Index, PSI: Processing Speed Index) and a Full Scale Intelligence Quotient (FSIQ). WISC-IV profiles of children with CTD-only, OCD-only, ADHD-only, CTD+ADHD, CTD+OCD and CTD+OCD+ADHD were compared with the WISC-IV norm (N = 1650, M = 100 and SD = 15) and among each other.

RESULTS

Unpaired t-tests revealed that children with ADHD-only showed significant lower PSI scores, whereas children with CTD-only and OCD-only had significant higher VCI scores as compared to the German WISC-IV norm. One-way ANOVA revealed that children with ADHD-only showed significant lower WMI scores as compared to children with CTD+OCD.

CONCLUSIONS

We were able to confirm previous evidence on WISC-IV profiles in ADHD in a German clinical sample and contribute new findings on cognitive performance in children with (non-)comorbid CTD and OCD that have to be seen in light of the study's limitations.

Candidate Genes and Pathways Associated with Gilles de la Tourette Syndrome-Where Are We?

Gilles de la Tourette syndrome (GTS) is a childhood-onset neurodevelopmental and -psychiatric tic-disorder of complex etiology which is often comorbid with obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD). Twin and family studies of GTS individuals have shown a high level of heritability suggesting, that genetic risk factors play an important role in disease etiology. However, the identification of major GTS susceptibility genes has been challenging, presumably due to the complex interplay between several genetic factors and environmental influences, low penetrance of each individual factor, genetic diversity in populations, and the presence of comorbid disorders. To understand the genetic components of GTS etiopathology, we conducted an extensive review of the literature, compiling the candidate susceptibility genes identified through various genetic approaches. Even though several strong candidate genes have hitherto been identified, none of these have turned out to be major susceptibility genes yet.