Epidemiological Survey of Tourette Syndrome in Children and Adolescents in Wenzhou of P.R. China

The role of neuroactive steroids in tic disorders

Tics are sudden, repetitive movements or vocalizations. Tic disorders, such as Tourette syndrome (TS), are contributed by the interplay of genetic risk factors and environmental variables, leading to abnormalities in the functioning of the cortico-striatal-thalamo-cortical (CSTC) circuitry. Various neurotransmitter systems, such as gamma-aminobutyric acid (GABA) and dopamine, are implicated in the pathophysiology of these disorders. Building on the evidence that tic disorders are predominant in males and exacerbated by stress, emerging research is focusing on the involvement of neuroactive steroids, including dehydroepiandrosterone sulfate (DHEAS) and allopregnanolone, in the ontogeny of tics and other phenotypes associated with TS. Emerging evidence indicates that DHEAS levels are significantly elevated in the plasma of TS-affected boys, and the clinical onset of this disorder coincides with the period of adrenarche, the developmental stage characterized by a surge in DHEAS synthesis. On the other hand, allopregnanolone has garnered particular attention for its potential to mediate the adverse effects of acute stress on the exacerbation of tic severity and frequency. Notably, both neurosteroids act as key modulators of GABA-A receptors, suggesting a pivotal role of these targets in the pathophysiology of various clinical manifestations of tic disorders. This review explores the potential mechanisms by which these and other neuroactive steroids may influence tic disorders and discusses the emerging therapeutic strategies that target neuroactive steroids for the management of tic disorders.

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 female Tourette patient: Sex differences in Tourette Disorder

Tourette Disorder (TD) is a male predominant neurodevelopmental disorder characterized by tics and frequent psychiatric comorbidities. Girls with TD have later peak symptoms, less remission with age, and worse impairment from tics, particularly in adulthood. Female TD patients are less likely to have Attention Deficit Hyperactivity Disorder and more likely to have anxiety and mood disorders. Hyperandrogenism is associated with TD in both sexes, and neuroanatomic sexual dimorphism is reduced in adult TD patients. Some women report catamenial tics, which may relate to estrogen withdrawal or rises in allopregnanolone. Limited data suggest that several neuroanatomic alterations present in boys with TD are not present in girls with TD. Female sex predicts better response to haloperidol. Further research into female tic pathophysiology may influence sex-specific treatment development.

Haloperidol ameliorates androgen-induced behavioral deficits in developing male rats

The purpose of present study was to infer the potential effects of testosterone increase in some male-based childhood-onset neuropsychiatric disorders, such as Tourette syndrome. Thus, the influence of early postnatal androgen exposure upon the neurobehaviors and its possible neural basis were investigated in the study. Male pup rats received consecutive 14-day testosterone propionate (TP) subcutaneous injection from postnatal day (PND) 7. The TP treatment produced the hyperactive motor behavior and grooming behavior as well as the increased levels of dopamine, tyrosine hydroxylase and dopamine transporter in the mesodopaminergic system and the elevated levels of serotonin in the nucleus accumbens, without affecting the levels of glutamate, γ-aminobutyric acid, norepinephrine and histamine in the caudate putamen and nucleus accumbens of PND21 and PND49 rats. Dopamine D2 receptor antagonist haloperidol was administered to the early postnatal TP-exposed PND21 and PND49 male rats 30 min prior to open field test. Haloperidol significantly ameliorated the motor behavioral and grooming behavioral defects induced by early postnatal TP exposure. The results demonstrated that early postnatal androgen exposure significantly disturbed the brain activity of developing male rats via enhancing the mesodopaminergic activity. It was suggested that abnormal increments of testosterone levels during the early postnatal development might be a potential risk factor for the incidence of some male-based childhood-onset neuropsychiatric disorders by affecting the mesodopaminergic system.

Gilles de la Tourette syndrome

Gilles de la Tourette syndrome (GTS) is a childhood-onset neurodevelopmental disorder that is characterized by several motor and phonic tics. Tics usually develop before 10 years of age, exhibit a waxing and waning course and typically improve with increasing age. A prevalence of approximately 1% is estimated in children and adolescents. The condition can result in considerable social stigma and poor quality of life, especially when tics are severe (for example, with coprolalia (swearing tics) and self-injurious behaviours) or when GTS is accompanied by attention-deficit/hyperactivity disorder, obsessive-compulsive disorder or another neuropsychiatric disorder. The aetiology is complex and multifactorial. GTS is considered to be polygenic, involving multiple common risk variants combined with rare, inherited or de novo mutations. These as well as non-genetic factors (such as perinatal events and immunological factors) are likely to contribute to the heterogeneity of the clinical phenotype, the structural and functional brain anomalies and the neural circuitry involvement. Management usually includes psychoeducation and reassurance, behavioural methods, pharmacotherapy and, rarely, functional neurosurgery. Future research that integrates clinical and neurobiological data, including neuroimaging and genetics, is expected to reveal the pathogenesis of GTS at the neural circuit level, which may lead to targeted interventions.

Practitioner Review: Treatments for Tourette syndrome in children and young people - a systematic review

BACKGROUND

Tourette syndrome (TS) and chronic tic disorder (CTD) affect 1-2% of children and young people, but the most effective treatment is unclear. To establish the current evidence base, we conducted a systematic review of interventions for children and young people.

METHODS

Databases were searched from inception to 1 October 2014 for placebo-controlled trials of pharmacological, behavioural, physical or alternative interventions for tics in children and young people with TS or CTD. Certainty in the evidence was assessed with the GRADE approach.

RESULTS

Forty trials were included [pharmacological (32), behavioural (5), physical (2), dietary (1)]. For tics/global score there was evidence favouring the intervention from four trials of α2-adrenergic receptor agonists [clonidine and guanfacine, standardised mean difference (SMD) = -0.71; 95% CI -1.03, -0.40; N = 164] and two trials of habit reversal training (HRT)/comprehensive behavioural intervention (CBIT) (SMD = -0.64; 95% CI -0.99, -0.29; N = 133). Certainty in the effect estimates was moderate. A post hoc analysis combining oral clonidine/guanfacine trials with a clonidine patch trial continued to demonstrate benefit (SMD = -0.54; 95% CI -0.92, -0.16), but statistical heterogeneity was high. Evidence from four trials suggested that antipsychotic drugs improved tic scores (SMD = -0.74; 95% CI -1.08, -0.40; N = 76), but certainty in the effect estimate was low. The evidence for other interventions was categorised as low or very low quality, or showed no conclusive benefit.

CONCLUSIONS

When medication is considered appropriate for the treatment of tics, the balance of clinical benefits to harm favours α2-adrenergic receptor agonists (clonidine and guanfacine) as first-line agents. Antipsychotics are likely to be useful but carry the risk of harm and so should be reserved for when α2-adrenergic receptor agonists are either ineffective or poorly tolerated. There is evidence that HRT/CBIT is effective, but there is no evidence for HRT/CBIT alone relative to combining medication and HRT/CBIT. There is currently no evidence to suggest that the physical and dietary interventions reviewed are sufficiently effective and safe to be considered as treatments.

VISIT-TS: A multimedia tool for population studies on tic disorders

Population-based assessment of Tourette syndrome (TS) and other tic disorders produces a paradox. On one hand, ideally diagnosis of tic disorders requires expert observation. In fact, diagnostic criteria for TS explicitly require expert assessment of tics for a definite diagnosis. On the other hand, large-scale population surveys with expert assessment of every subject are impracticable. True, several published studies have successfully used expert assessment to find tic prevalence in a representative population (e.g. all students in a school district). However, extending these studies to larger populations is daunting.

We created a multimedia tool to demonstrate tics to a lay audience, discuss their defining and common attributes, and address features that differentiate tics from other movements and vocalizations. A first version was modified to improve clarity and to include a more diverse group in terms of age and ethnicity. The result is a tool intended for epidemiological research. It may also provide additional benefits, such as more representative minority recruitment for other TS studies and increased community awareness of TS.

A proprietary herbal medicine (5-Ling Granule) for Tourette syndrome: a randomized controlled trial

BACKGROUND

Tourette syndrome (TS) is a common tic disorder in children and adolescents. There is preliminary evidence that herbal medicine may possess the potential to treat tics. The purpose of this study was to formally evaluate the efficacy and safety of 5-Ling Granule (5-LGr), a proprietary polyherbal product, for the treatment of patients with TS in comparison with tiapride and placebo.

METHODS

In this multisite, double-blind, double-dummy, randomized, placebo-controlled trial, 603 patients with TS aged 5-18 years were randomly assigned to treatment with placebo (n = 117), tiapride (n = 123, 200-400 mg/day) or 5-LGr (n = 363, 15-22.5 g/day) for 8 weeks. The primary outcome was measured using the Yale Global Tic Severity Scale (YGTSS) and its subscales, total tic Score (TTS) and tic-related impairment. Incidence of adverse events was compared among the three groups.

RESULTS

While tics of all patients were reduced over time, 5-LGr and tiapride treatment produced significantly greater improvement on the YGTSS overall scale and subscale for TTS and impairment at endpoint than the placebo. Seventy-four percentage of patients in the 5-LGr arm and 68.3% in the tiapride arm had clinical response and these rates of response were significantly higher than those on placebo (44.0%, p < .001). The incidence of overall adverse events was significantly fewer for patients on placebo and 5-LGr compared to tiapride (11.2% and 13.8% vs. 26.0%, p = .002); in particular physical tiredness, dizziness and sleep disturbance.

CONCLUSIONS

The clinical efficacy of 5-LGr is comparable to tiapride in reducing tics. Its safety profile is better than tiapride. 5-LGr can be considered a safe and effective therapy for TS (Trial registration: www.clinicaltrials.gov: NCT01501695).

The effectiveness and safety of plum-blossom needle therapy for Tourette syndrome: study protocol for a randomized controlled trial

Background

Previous studies have indicated that acupuncture can alleviate the symptoms of Tourette syndrome (TS), but the evidence is insufficient. So far, there have been no reports on plum-blossom needle therapy for TS. Here we present a protocol for a randomized controlled trial using plum-blossom needle therapy to treat TS.

Methods/design

Sixty patients will be randomly allocated into either the plum-blossom needle therapy group or the habit reversal training (HRT) group. All patients in each group will be given 12 weeks of treatment, with follow-up at the 24th week. The primary outcome measure will be the mean change from baseline in the total tic score on the Yale Global Tic Severity Scale (YGTSS) at the 12th week. Secondary outcome measures will include the scores on the TS Clinical Global Impression Scale (CGI) and the mean changes from baseline in the YGTSS score and the Children and Adolescents’ Quality of Life Scale (CAQOL) at other time points. Safety will also be evaluated.

Discussion

This trial will evaluate the effectiveness and safety of plum-blossom needle therapy for TS compared with HRT. A limitation of this trial is that patients and acupuncturists cannot be blinded.

Trial registration

ClinicalTrials.gov Identifier: NCT02403258 (Date of registration: March 31, 2015).

Pediatric suppositories of sulpiride solid dispersion for treatment of Tourette syndrome: in vitro and in vivo investigations

Pharmaceutical development was adopted in the current study to propose a pediatric rectal formulation of sulpiride as a substitute to the available oral or parenteral formulations in the management of Tourette syndrome (TS). The goal was to formulate a product that is easy to use, stable, and highly bioavailable and to achieve a rapid clinical efficacy. Towards this aim, sulpiride solid dispersion (SD) with tartaric acid at a weight ratio of 1:0.25 was incorporated into different suppository bases, namely witepsol W25, witepsol H15, witepsol E75, suppocire NA, suppocire A, glycerogelatin, and polyethylene glycols. The formulae were evaluated in vitro using different pharmacotechnical methods such as visual, melting, weight and content uniformities, drug release, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and X-ray diffraction (XRD) analyses. In vivo bioavailability was also assessed in rabbits to compare the bioavailability of either raw sulpiride-incorporated or its SD-incorporated witepsol H15-based suppositories to its oral suspension (reference). Sulpiride SD-incorporated witepsol H15 formulation showed acceptable in vitro characteristics with a bioavailability of 117% relative to oral dosing, which excel that in humans (27% after dosing of oral product). In addition, the proposed formula not only passed the 6-month stability study but also proposed a promising scale-up approach. Hence, it showed a great potential for pediatric product development to manage TS in rural areas.

Current state and recent developments of child psychiatry in China

China has a population of 1.3 billion, of which 238 million are children under age 15. The rapid economic development and social reforms that have taken place in recent years all had a great influence on child and adolescent mental health. Though a nationwide prevalence study for child and adolescent mental disorders in China is lacking, several regional studies have shown the prevalence of mental disorders in children to be close to the worldwide prevalence of 20%. This article reviews the current status of Chinese child psychiatry, the prevalence of specific disorders in China and the influence of culture on the diagnosis and treatment of child and adolescent mental disorders. Several important social issues are also explored in detail, including the one child policy and left-behind children of migrating workers. Changes in family structures along with the growing competitions in life have weakened the traditional social support system. As a result childhood behavioral problems, mood disorders in young college students, substance abuse and youth suicide are all increasing in China. Many who suffer from mental disorders are not adequately cared for because the scarcity of qualified service providers and pathways to care. This article also lists some challenges and possible solutions, including the multidisciplinary and culture sensitive service model for child mental health. Relevant laws, policies and regulations are also introduced.

A personal 35 year perspective on Gilles de la Tourette syndrome: prevalence, phenomenology, comorbidities, and coexistent psychopathologies

This Series is a personal narrative of my experience with patients with Gilles de la Tourette syndrome and covers its definition and history since the first description in 1825. Controversy entered the prevalence debate early. Although originally considered very rare, in the 1980s, Tourette's syndrome was reported to be common. However, Tourette's syndrome has been shown to occur at a prevalence of about 0·85% to 1%. Tourette's syndrome is more common in the male population, more prominent during childhood, and usually improves, but does not disappear with age. Tourette's syndrome is considered less common in people of sub-Saharan black African, African-American, and American Hispanic ethnic origin. The phenomenology is similar worldwide, indicating a biological basis. The hallmark characteristics are multiple motor and one or more vocal/phonic tics. Other associated features include premonitory urges, a waxing and waning course, and to a much lesser degree, coprolalia. Comorbid disorders are common and are suggested to include obsessive-compulsive disorder and behaviours, attention deficit hyperactivity disorder, and autistic spectrum disorder. Coexistent psychopathologies are suggested to include depression and conduct and personality disorders. Importantly, I argue that Tourette's syndrome is not a unitary condition. Finally, I offer suggestions for future research.

Population prevalence of Tourette syndrome: a systematic review and meta-analysis

The aim of this study was to refine the population prevalence estimate of Tourette Syndrome (TS) in children and to investigate potential sources of heterogeneity in previously published studies. A systematic review was conducted and all qualifying published studies of TS prevalence were examined. Extracted data were subjected to a random-effects meta-analysis weighted by sample size; meta-regressions were performed to examine covariates that have previously been proposed as potential sources of heterogeneity. Twenty-six articles met study inclusion criteria. Studies derived from clinically referred cases had prevalence estimates that were significantly lower than those derived from population-based samples (P = 0.004). Among the 21 population-based prevalence studies, the pooled TS population prevalence estimate was 0.52% (95% confidence interval CI: 0.32-0.85). In univariable meta-regression analysis, study sample size (P = 0.002) and study date (P = 0.03) were significant predictors of TS prevalence. In the final multivariable model including sample size, study date, age, and diagnostic criteria, only sample size (P < 0.001) and diagnostic criteria (omnibus P = 0.003; Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision [DSM-IV-TR]: P = 0.005) were independently associated with variation in TS population prevalence across studies. This study refines the population prevalence estimate of TS in children to be 0.3% to 0.9%. Study sample size, which is likely a proxy for case assessment method, and the use of DSM-IV-TR diagnostic criteria are the major sources of heterogeneity across studies. The true TS population prevalence rate is likely at the higher end of these estimates, given the methodological limitations of most studies. Further studies in large, well-characterized samples will be helpful to determine the burden of disease in the general population.

The prevalence of tic disorders in children and adolescents in Brazil

Tourette syndrome (TS) and tic disorders represent events of familiar magnitude characterized by involuntary movements and/or vocalization. To determine the prevalence of TS/tic disorders we studied a sample of 762 subjects (388 M, 374 F), between 1992 and 1997, age 6 to 43 years old, taken out of a population of 10,155 subjects (4,918 M, 5,237 F; age: 3-56 years old). A structured 4-item questionnaire, direct interview (multistaged), >1 yr follow-up, were used. 9,565 subjects (4,614 M, 4,951 F) sent back the questionnaires, 3,354 of these (1,671 M, 1,683 F) with positive answers to tics. 42 subjects (31 M, 11 F, age: 7-21 years old, mean: 11 years old) met the DSM-III-R criteria. The total minimal prevalence of TS is 0.43%, with a 3:1 ratio male/female. The minimal prevalence of chronic tic disorder is 2.27%. The total minimal prevalence for tic disorders at all is 2.91%. No special education students participation.

The Prevalence of Tic Disorders and Clinical Characteristics in Children

BACKGROUND

Prevalence is a simple statement about the frequency of a disease in the population. For many medical conditions, including Tourette syndrome, there are true cases that have not been previously diagnosed due to problems of access to appropriate clinical services. Therefore, to obtain a trustworthy estimate of prevalence, it is necessary to go beyond cases identified in clinical settings and evaluate community samples.

METHOD

We reviewed 11 community surveys in children with Tourette syndrome (TS) published since 2000. We also examined the frequency of co-occurring psychiatric conditions in community samples and large clinically-ascertained samples.

RESULTS

Transient tics are relatively common affecting as many as 20% of school-age children. The 11 studies reviewed here offer a wide range of estimates from 2.6 to 38 per 1000 children for TS. Six studies provide estimates in a narrower range from 4.3 to 7.6 per 1000, but the confidence interval around this narrower range remains wide. Six studies provided results on chronic tic disorders ranging from 3 to 50 per 1000 for Chronic Motor Tic Disorder and 2.5 to 9.4 per 1000 for Chronic Vocal Tic Disorder. Community samples and large clinically-ascertained samples consistently show high rates of ADHD, disruptive behavior and anxiety disorders in children with TS.

CONCLUSIONS

The wide range of prevalence estimates for TS and chronic tic disorders is likely due to differences in sample size and assessment methods. The best estimate of prevalence for TS in school-age children is likely to fall between 4 and 8 cases per 1000. Clinical assessment of children with chronic tic disorders warrants examination of other problems such as ADHD, disruptive behavior and anxiety.

Factors associated with newly diagnosed tic disorders among children in Taiwan: a 10-year nationwide longitudinal study

Increased attention has been paid to tic disorders clinically, yet relatively few studies have probed potential factors that account for the occurrence of tic disorders in the general population. In this study, we used data derived from the Taiwan's National Health Insurance Research Database to examine an array of factors related to the diagnosis of tic disorders and to further probe gender heterogeneity in clinical manifestation. Poisson regression analyses were applied to model the effects of birth cohort, period, and age, separately, on tic disorders. A total of 880 newly diagnosed tic disorders were identified from 2002 to 2009 among 100,516 youngsters in the study dataset who were born between 1997 and 2005. The results showed that a significant increase in the adjusted incidence rate ratio (IRR) was observed when age increased, with the highest adjusted IRR found at age 8-9 years. Compared to the time period from 2002 to 2005, an elevated IRR was found in the time period from 2006 to 2009 (adjusted IRR: 1.37; 95% CI: 1.05-1.80). Boys tended to be more likely to receive their initial diagnosis from psychiatrists and have higher comorbid attention-deficit/hyperactivity disorder (ADHD), as compared with their girl counterparts. In conclusion, the findings indicate that the effects of age and period, respectively, influence the occurrence of newly diagnosed tic disorders. Gender difference and higher frequent comorbid ADHD in boys than in girls were observed in this study.

Neuroendocrine aspects of Tourette syndrome

There is sparse evidence suggesting the participation of neuroendocrine mechanisms, mainly involving sex and stress steroid hormones, to the pathophysiology of neurodevelopmental disorders such as Tourette syndrome (TS) and obsessive-compulsive disorder (OCD). Patients with TS exhibit a sex-specific variability in gender distribution (male/female ratio=3-4/1) and in its natural history, with a severity peak in the period around puberty. The administration of exogenous androgens may worsen tics in males with TS, whereas drugs counteracting the action of testosterone might show some antitic efficacy. This suggests a higher susceptibility of patients with TS to androgen steroids. There are insufficient data on the regulation of the hypothalamic-pituitary-gonadal (HPG) axis in TS. However, preliminary evidence suggests that a subgroup of women with TS might be more sensitive to the premenstrual trough of estrogen levels. Patients with TS exhibit differences in a number of behavioral, cognitive, and anatomical traits that appear to be sex related. There is a body of evidence supporting, albeit indirectly, the hypothesis of an increased exposure to androgenic steroids during the very early phases of neural development. Animal models in rodents suggest a complex role of gonadal hormones upon the modulation of anxiety-related and stereotyped behaviors during adult life. Patients with TS exhibit an enhanced reactivity of the hypothalamic-pituitary-adrenal axis to external stressors, despite a preserved diurnal cortisol rhythm and a normal restoration of the baseline activity of the axis following the acute stress response. Preliminary evidence suggests the possible implication of oxytocin (OT) in disorders related to the TS spectrum, especially non-tic-related OCD. The injection of OT in the amygdala of rodents was shown to be able to induce hypergrooming, suggesting the possible involvement of this neuropeptide in the pathophysiology of complex, stereotyped behaviors. In contrast, there is anecdotal clinical evidence that tics improve following periods of affectionate touch and sexual intercourse.

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

This study evaluated the prevalence of tic disorders. MEDLINE and EMBASE databases were searched, using terms specific to Tourette syndrome and tic disorders, for studies of incidence, prevalence, and epidemiology. Thirty-five studies reporting data from 1985-2011 on the incidence or prevalence of tic disorders in a defined population were included. One reported incidence, and 34 reported prevalence. Meta-analysis of 13 studies of children yielded a prevalence of Tourette syndrome at 0.77% (95% confidence interval, 0.39-1.51%). Prevalence is higher in boys: 1.06% of boys were affected (95% confidence interval, 0.54-2.09%) vs 0.25% of girls (95% confidence interval, 0.05-1.20%). Transient tic disorder comprised the most common tic disorder in children, affecting 2.99% (95% confidence interval, 1.60-5.61%). Meta-analysis of two studies assessing adults for Tourette syndrome revealed a prevalence of 0.05% (95% confidence interval, 0.03-0.08%). The prevalence of tic disorders was higher in all studies performed in special education populations. Tic disorders are more common in children than adults, in boys than girls, and in special education populations. Parents, educators, healthcare professionals, and administrators should be aware of the frequency with which tic disorders occur, and ensure proper access to appropriate care.

Review of prevalence studies of tic disorders: methodological caveats

INTRODUCTION

Tic disorders are neurodevelopmental disorders of childhood associated with psychiatric comorbidity and academic problems. Estimating the prevalence and understanding the epidemiology of tic disorders is more complex than was once thought. Until fairly recently, tic disorders were thought to be rare, but today tics are believed to be the most common movement disorder, with 0.2-46.3% of schoolchildren experiencing tics during their lifetime. Tentative explanations for differing prevalence estimates include the multidimensional nature of tics with a varied and heterogeneous presentation, and the use of different epidemiological methods and study designs.

METHODS

Literature review and analysis of methodological issues pertinent to epidemiological studies of tic disorders.

RESULTS

Epidemiological studies of tic disorders were reviewed, and the main elements of epidemiological studies, including sample selection, case ascertainment strategy, definition of tic disorders, and the degree of coverage of the eligible population (i.e., the response rate) were examined.

DISCUSSION

In order to improve the quality of epidemiological studies of tic disorders, a number of recommendations were made, including but not limited to a review of the diagnostic criteria for tic disorders, and inclusion of new tic disorder categories for those with tics of secondary etiology.

Prevalence of tics in schoolchildren in central Spain: a population-based study

Tic disorders constitute a neurodevelopmental disorder of childhood. This study sought to determine the prevalence of tic disorders in a school-based sample. A randomized sample of 1158 schoolchildren, based on clusters (classrooms) in the province of Burgos (Spain), was identified on a stratified sampling frame combining types of educational center and setting (mainstream schools and special education), using a two-phase approach (screening and diagnosis ascertainment by a neurologist). Tics with/without impairment criterion were diagnosed according to Diagnostic and Statistical Manual of Mental Disorders criteria. In mainstream schools, tics were observed in 125/741 students (16.86%; 95% confidence interval, 14.10-19.63), and were more frequent in boys (87/448, 19.42%; 95% confidence interval, 15.64-23.19) compared with girls (38/293, 12.96%; 95% confidence interval, 8.95-16.98; P = 0.03). In special education centers, tics disorders were observed in 11/54 of children (20.37%; 95% confidence interval, 8.70-32.03). Overall, tics with impairment criteria were less frequent than tics without impairment criteria (4.65% vs 11.85%, P < 0.0001). The most frequent diagnoses involved chronic motor tics (6.07%) and Tourette syndrome (5.26%). Tic disorders are common in childhood, and the use or nonuse of impairment criteria exerts a significant impact on tic prevalence estimates.

Tourette syndrome and excitatory substances: is there a connection?

BACKGROUND AND PURPOSE

The objective of this study is to investigate the relationship between excitatory substances by testing the urine in children with Tourette syndrome (TS).

METHODS

We performed a control study involving 44 patients with TS and 44 normal children by investigating the children's daily eating habits. We used the gas chromatograph-mass spectrometer and liquid chromatograph-mass spectrometer from Agilent. Substances for detection included 197 excitatory substances prohibited by the International Olympic Committee and other substances with similar chemical structures or biological functions for urine samples.

RESULTS

Forty-four patients who did not take any drugs in the past 2 weeks enrolled in the study. The positive rate in the experiment group was three cases, while it was negative in the control group. The level of 1-testosterone increased in one extremely severe TS patient who ate large amounts of puffed food and drank an average of 350 ml of cola per day. Cathine and other substances with similar chemical constitution or similar biological effects increased in one severe TS patient who ate bags of instant noodles daily, according to the high score of the Yale Global Tic Severity Scale.

CONCLUSION

An increase in ephedrine type, testosterone, and stimulants may be related to the pathogenesis of TS. Unhealthy food possibly causes TS. The relationship between excitatory substances and TS needs to be explored with the goal of providing more information on diagnosing and treating TS.

Validation of screening instruments for neuroepidemiological surveys of tic disorders

BACKGROUND

The main purpose was to validate a multistage protocol to screen tic disorders in mainstream and special education centers and to investigate whether telephone-based interviews were accurate to diagnose tic disorders when compared with in-person neurological interviews.

METHODS

A school-based survey of children and adolescents (6-16 years). A proxy report questionnaire for tic disorders was completed by teachers, observers, and parents. The diagnosis was confirmed by the neurologist based on the Diagnostic and Statistical Manual of Mental disorders (DSM-IV TR) criteria. The sensitivity, specificity, positive and negative predictive values, the likelihood ratio for a positive result (LR+), and the Kappa coefficients (k) for telephone-based interviews reliability were calculated.

RESULTS

One hundred twenty subjects, 57 from special education center and 63 from a mainstream school were studied. The sensitivity of the proxy report questionnaire was 58% and 36% when completed by the observers (mainstream and special education center, respectively), 40 and 73% when completed by the teachers, and 58 and 36% when completed by the parents. Using any of these 3 screening sources, the sensitivity was 92%, the positive predictive value was 38%, and negative predictive value was 97% (mainstream schools), whereas the sensitivity was 82%, the positive predictive value was 20%, and negative predictive value was 82% (special education centers). Parents (mainstream schools) and teachers (special education center) produced the highest LR+ (7.25 and 1.26, respectively) and the intraobserver reliability of the telephone-based interviews versus in-person neurological interviews gave a k coefficient of 0.83.

CONCLUSIONS

The efficiency of different screening instruments for tic disorders seems to vary in different settings. Telephone-based interviews may be a valid and convenient backup to ascertain the diagnosis of tic disorders when face-to-face neurological examination is not possible.

The immunobiology of Tourette's disorder, pediatric autoimmune neuropsychiatric disorders associated with Streptococcus, and related disorders: a way forward

Obsessive-compulsive disorder (OCD) and related conditions including Tourette's disorder (TD) are chronic, relapsing disorders of unknown etiology associated with marked impairment and disability. Associated immune dysfunction has been reported and debated in the literature since the late 80s. The immunologic culprit receiving the most interest has been Group A Streptococcus (GAS), which began to receive attention as a potential cause of neuropsychiatric symptoms, following the investigation of the symptoms reported in Sydenham's chorea (SC) and rheumatic fever, such as motor tics, vocal tics, and both obsessive-compulsive and attention deficit/hyperactivity symptoms. Young children have been described as having a sudden onset of these neuropsychiatric symptoms temporally associated with GAS, but without supporting evidence of rheumatic fever. This presentation of OCD and tics has been termed pediatric autoimmune neuropsychiatric disorders associated with Streptococcus (PANDAS). Of note, SC, OCD, and TD often begin in early childhood and share common anatomic areas--the basal ganglia of the brain and the related cortical and thalamic sites--adding support to the possibility that these disorders might share a common immunologic and/or genetic vulnerability. Relevant manuscripts were identified through searches of the PsycINFO and MedLine databases using the following keywords: OCD, immune, PANDAS, Sydenham chorea, Tourette's disorder Group A Streptococcus. Articles were also identified through reference lists from research articles and other materials on childhood OCD, PANDAS, and TD between 1966 and December 2010. Considering the overlap of clinical and neuroanatomic findings among these disorders, this review explores evidence regarding the immunobiology as well as the relevant clinical and therapeutic aspects of TD, OCD, and PANDAS.

Aripiprazole for the treatment of adolescent Tourette's syndrome: a case report

Gilles de la Tourette syndrome (GTS) is a neuropsychiatric, lifelong disorder with onset in childhood. The essential features of this disorder are multiple motor tics and one or more vocalizations. The neurochemical pathophysiology of GTS involves an unknown abnormality in the central dopaminergic system. Atypical antipsychotics, such as aripiprazole, serve as a new therapeutic option for GTS. The authors describe a unique case of Tourette's syndrome (TS) in an adolescent in which aripiprazole resolved the patient's symptoms. A 17-year-old, 5'11'' tall, African American male weighing 220 lbs was diagnosed with TS at 9 years old. By age 16, the patient developed prominent symptoms of intermitted eye blinking, forehead raising, finger snapping, heavy breathing, and head bobbing. Clonidine, in addition to homeopathic remedies (N-acetylcholine and alpha lipoic acid), was administered to the patient without significant diminution of symptoms. Later, aripiprazole was initiated at 5 mg/d. As a result, noticeable symptomatic improvement occurred within 48 hours. Aripiprazole was titrated over the next 4 weeks to 6.5 mg/d, with significant results. Over the next 6 months, aripiprazole was titrated again to 10 mg/d with additional symptom reduction. This case illustrates a patient who responded to aripiprazole with no reported adverse effects, when standard therapy failed to improve symptoms.

The international prevalence, epidemiology, and clinical phenomenology of Tourette syndrome: a cross-cultural perspective

The overall international prevalence of Tourette syndrome (TS) is 1% in the majority of cultures of the world. Both TS and tics are certainly more obvious and may be more common in younger people. Moreover, TS is seen less frequently in some cultures. However, in all cultures where it has been reported, the phenomenology is similar, highlighting the biological underpinnings of the disorder. This article reviews the international prevalence, epidemiology, and clinical phenomenology of TS, from a cross-cultural perspective.

The diagnosis of Tourette's Syndrome: communication and impact

No study to date has investigated differences in perception regarding the manner in which a diagnosis of Tourette's Syndrome (TS) is communicated and the impact that this diagnosis can have on patients, as well as their relatives and physicians. The main objective was to explore the personal experiences regarding the communication and impact of a TS diagnosis on those who receive the diagnosis, their caregivers and physicians. A qualitative research methodology was used in this study, based on the use of focus groups (FGs). All health professionals, persons with TS and their relatives said that TS was difficult to diagnose. However, each group perceived different causes for the difficulty. Physicians cited the complexity of the symptoms, while the patients themselves noted the general lack of knowledge regarding the disease. In adittion, the physicians and the relatives both noted that the symptoms of TS were often hidden behind family guilt. The communication of the diagnosis to relatives of children with TS was not adequate because of poor understanding and interpretation of the clinical terminology. The most important conclusion was that the current method for communicating the diagnosis of TS to patients and relatives should be improved to facilitate better understanding and interpretation.

The prevalence and epidemiology of Gilles de la Tourette syndrome. Part 2: tentative explanations for differing prevalence figures in GTS, including the possible effects of psychopathology, aetiology, cultural differences, and differing phenotypes

As has been demonstrated, Gilles de la Tourette Syndrome (GTS) occurs in at least 1% of the population worldwide. However, earlier studies suggested a lower prevalence. In addition, the prevalence figures for different studies very between 0.4% and 3.8%. Moreover, the prevalence appears to vary in some parts of the world and races, with a lower rate in Afro-Americans and sub-Saharan black Africans. In this the second part of the review, possible reasons for the differences in prevalence and epidemiology are discussed. Tentative explanations for differing prevalence figures in GTS include problems with the diagnosis of GTS, the multidimensional nature of tics, as well as other tic factors including the waxing and waning of symptoms and the suppressibility of symptoms. Other factors inherent to GTS include the fact that there is no diagnostic test and indeed no definitive diagnosis other than clinical, the fact that psychosocial stresses can lead to increased tic severity, and that comorbid disorders may mask tics. The varying methods of study employed can also effect prevalence. There may be some regional differences in GTS as well, which may be due to a lack of awareness of GTS, or it may be a true reflection of low prevalence as in some populations GTS does appear rare. With regard to the sub-Saharan Africa data and possibly the African American data, matters are much more complex than meets the eye. The following reasons are all possible for the apparent rarity in these populations and include (i) other medical priorities and less propensity to seek health care, (ii) lack of awareness of GTS, (iii) chance, (iv) ethnic and epigenetic differences and reasons, (v) genetic and allelic differences in different races, and (vi) an admixture of races. The aetiology of GTS is also complex, with influences from complex genetic mechanisms, pre- and perinatal difficulties and, in a subgroup, some infections, possibly by epigenetic mechanisms. These may well affect phenotype and, thus, prevalence. There have even been suggestions that people with GTS are increasing. Recent data suggests that GTS is not a unitary condition and that there may well be different types of GTS. The prevalence of GTS in these individual subtypes is unknown. It is suggested that a new nomenclature be adopted for GTS in future, pending further genetic and phenomenological studies. To what extent the aetiology affects the phenotype and, thus, the prevalence is still unclear.

The prevalence and epidemiology of Gilles de la Tourette syndrome. Part 1: the epidemiological and prevalence studies

The prevalence and epidemiology of Gilles de la Tourette syndrome (GTS) are more complex than was once thought. Until fairly recently, GTS was thought to be a rare and, according to some, a psychogenically mediated disorder. Prevalence depends, at least in part, on the definition of GTS, the type of ascertainment, and epidemiological methods used. However, in dedicated specialist GTS clinics, the majority of patients were noted to have positive family histories of tics or GTS, and large, extended, multiply-affected GTS pedigrees indicated that many family members had undiagnosed tics or GTS: it was therefore realized that GTS was far from uncommon. Seven early epidemiological studies reported that GTS was uncommon or rare for a variety of reasons. More recently, however, two pilot studies and 12 large definitive studies in mainstream school and school-age youngsters in the community, using similar multistage methods, have documented remarkably consistent findings, demonstrating prevalence figures for GTS of between 0.4% and 3.8% for youngsters between the ages of 5 and 18 years. Of the 420,312 young people studied internationally, 3,989 (0.949%) were diagnosed as having GTS. It is therefore suggested that a figure of 1% would be appropriate for the overall international GTS prevalence figure. There were however, "outliers" to the figure. For instance, GTS does seem to be substantially rarer in African-American people and has been reported only very rarely in sub-Saharan black African people. GTS is found in all other cultures, although to possibly differing degrees. In all cultures where GTS has been reported, the phenomenology is similar, highlighting the biological underpinnings of the disorder.

The influence of contextual factors on tic expression in Tourette's syndrome: a review

Symptoms of Tourette's syndrome vary in frequency and intensity. Although such variability may be the result of deficits in the underlying neurological system, tic expression can also be systematically impacted by contextual factors. This article reviews research on the impact of several contextual factors on tic expression and discusses implications for future research and treatment development.

Attention-deficit/hyperactivity disorder, Tourette's syndrome, and restless legs syndrome: the iron hypothesis

Preliminary but increasing evidence suggests that attention-deficit/hyperactivity disorder (ADHD), Tourette's syndrome (TS), and restless legs syndrome (RLS) may be comorbid. In the present article, we hypothesize that ADHD, TS, and RLS may be part of a spectrum, and that iron deficiency contributes to the pathophysiology underlying this spectrum. Iron deficiency might lead to ADHD, RLS and TS symptoms via its impact on the metabolism of dopamine and other catecholamines, which have been involved into the pathophysiology of ADHD, TS, and RLS. We speculate that the catecholaminergic systems are differently impacted in each of the three disorders, contributing to a different specific phenotypic expression of iron deficiency. MRI studies assessing brain iron levels in ADHD, TS, and childhood RLS, as well as genetic studies on the specific molecular pathways involved in iron deficiency, are greatly needed to confirm the iron hypothesis underlying ADHD, TS, and RLS. This body of research may set the basis for controlled trials assessing the effectiveness and tolerability, as well as the most appropriate dose, duration and type (oral vs. intravenous) of iron supplementation. In conclusion, the iron hypothesis may help us progress in the understanding of pathophysiological links between ADHD, RLS, and TS, suggesting that iron supplementation might be effective for all these three impairing conditions.

Prospective randomized double-blind trial of bilateral thalamic deep brain stimulation in adults with Tourette syndrome

Object

The severity of Tourette syndrome (TS) typically peaks just before adolescence and diminishes afterward. In some patients, however, TS progresses into adulthood, and proves to be medically refractory. The authors conducted a prospective double-blind crossover trial of bilateral thalamic deep brain stimulation (DBS) in five adults with TS.

Methods

Bilateral thalamic electrodes were implanted. An independent programmer established optimal stimulator settings in a single session. Subjective and objective results were assessed in a double-blind randomized manner for 4 weeks, with each week spent in one of four states of unilateral or bilateral stimulation. Results were similarly assessed 3 months after unblinded bilateral stimulator activation while repeated open programming sessions were permitted.

Results

In the randomized phase of the trial, a statistically significant (p < 0.03, Friedman exact test) reduction in the modified Rush Video-Based Rating Scale score (primary outcome measure) was identified in the bilateral on state. Improvement was noted in motor and sonic tic counts as well as on the Yale Global Tic Severity Scale and TS Symptom List scores (secondary outcome measures). Benefit was persistent after 3 months of open stimulator programming. Quality of life indices were also improved. Three of five patients had marked improvement according to all primary and secondary outcome measures.

Conclusions

Bilateral thalamic DBS appears to reduce tic frequency and severity in some patients with TS who have exhausted other available means of treatment.

Tourette syndrome and tic disorders: a decade of progress

OBJECTIVE

This is a review of progress made in the understanding of Tourette syndrome (TS) during the past decade including models of pathogenesis, state-of-the-art assessment techniques, and treatment.

METHOD

Computerized literature searches were conducted under the key words "Tourette syndrome," "Tourette disorder," and "tics." Only references from 1996-2006 were included.

RESULTS

Studies have documented the natural history of TS and the finding that tics usually improve by the end of the second decade of life. It has also become clear that TS frequently co-occurs with attention-deficit/hyperactivity disorder), obsessive-compulsive disorder, and a range of other mood and anxiety disorders. These comorbid conditions are often the major source of impairment for the affected child. Advances have also been made in understanding the underlying neurobiology of TS using in vivo neuroimaging and neurophysiology techniques. Progress on the genetic front has been less rapid. Proper diagnosis and education (involving the affected child and his or her parents, teachers, and peers) are essential prerequisites to the successful management of children with TS. When necessary, modestly effective antitic medications are available, although intervening to treat the comorbid attention-deficit/hyperactivity disorder and/or obsessive-compulsive disorder is usually the place to start.

CONCLUSIONS

Prospective longitudinal studies and randomized clinical trials have led to the refinement of several models of pathogenesis and advanced our evidence base regarding treatment options. However, fully explanatory models are needed that would allow for more accurate prognosis and the development of targeted and efficacious treatments.

Clinical effectiveness of quetiapine in children and adolescents with Tourette's syndrome : a retrospective case-note survey

BACKGROUND AND OBJECTIVE

Tourette's syndrome is a relatively common biological genetic disorder with a broad spectrum of neurobehavioural manifestations. Unfortunately, treatment of the condition is often unsatisfactory and all available drugs are associated with potential adverse effects. We therefore aimed to investigate the efficacy of quetiapine, a newer atypical antipsychotic, in the treatment of children and adolescents with Tourette's syndrome.

METHODS

This was a retrospective study carried out in outpatient clinics. Twelve patients aged 8-18 years with Tourette's syndrome (diagnosed according to Diagnostic and Statistical Manual IV criteria) who were receiving quetiapine therapy and had no diagnosis of epilepsy, major depression or psychotic disorder, were included in the study. The main outcome measure was the Yale Global Tic Severity Scale (YGTSS) score.

RESULTS

The initial dose of quetiapine was 25 mg/day, but the mean dose was increased to 114.6 +/- 51.6 mg/day and 175.0 +/- 116.8 mg/day at the fourth and eighth weeks of treatment, respectively. The YGTSS score, which was 21.6 +/- 4.0 at baseline, showed significant decreases at 4 and 8 weeks (reducing to 7.5 +/- 7.4 and 5.6 +/- 8.1, respectively; p < 0.003). Routine laboratory parameters and serum prolactin level were all normal and did not change throughout treatment. Mild but significant increases in both bodyweight and body mass index at 4 and 8 weeks compared with baseline were observed.

CONCLUSION

Other than causing mild weight gain, quetiapine appears to be an effective, safe and well tolerated drug in children and adolescents with Tourette's syndrome.

Prevalence of tic disorder in two schools in the Basque country: Results and methodological caveats

Different studies have shown that the prevalence of tic disorder is highly variable, depending on the methodology employed. The aim of this study was to determine the prevalence of tic disorder among children of two schools. The study was conducted in three successive steps: information to parents and teachers by way of speeches and projection of videotapes; anonymous fulfilling of an ad hoc questionnaire by teachers and parents and identification of children as "possible tic disorder" according to the questionnaire; and confirmation of the presence of tics by direct observation of children at school (20 minutes in each classroom). Eight hundred sixty-seven children were included. Age ranged from 4 to 16 years. Ninety percent of parents and 99% of teachers fulfilled the questionnaire. Seventy-one children had tics according to parents' and 50 according to teachers' opinion (both coincided in 23 cases). Fifty-seven cases were identified after direct observation in the classroom (prevalence of 6.5%). The vast majority of tics were mild in severity and duration. Prevalence obtained in this study was comparable with data reported in studies using a similar methodology, which is higher than results shown in early studies addressed with less rigid methodology. Most of identified cases were quite mild, not leading to major functional disability. In spite of the methodology employed, it is possible that some cases were lost.