Prevalence of Gilles de la Tourette's syndrome in North Dakota adults

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.

A 2-year longitudinal follow-up of quantitative assessment neck tics in Tourette's syndrome

Background

Neck motor tics in Tourette’s syndrome can cause severe neck complications. Although addressed in a few longitudinal studies, the clinical course of Tourette’s syndrome has not been quantitatively assessed. We had previously developed a method for quantifying the angular movements of neck tics using a compact gyroscope. Here, we present a follow-up study aimed at elucidating the clinical course of neck tics at both the group and individual levels.

Methods

Eleven patients with Tourette’s syndrome from our previous study participated in the present study, and their neck tics were recorded during a 5-min observation period. The severity of neck symptoms was assessed using the Yale Global Tic Severity Scale. The peak angular velocities and accelerations, tic counts, and severity scores in our previous study (baseline) and the present study (2-year follow-up) were compared at the group and individual levels. The individual level consistency between baseline and follow-up were calculated using intra-class correlation coefficients (ICCs, one-way random, single measure).

Results

At the group level, no significant change was observed between baseline and follow-up. At the individual level, angular velocity (ICC 0.73) and YGTSS scores (ICC 0.75) had substantial consistency over the two time points, and angular acceleration (ICC 0.59) and tic counts (ICC 0.69) had moderate consistency.

Conclusions

The intensity and frequency of neck tics did not change over time. Therefore, quantification of angular neck motor tics will aid in identifying patients with neck tics at high risk for severe neck complications.

Influence of Gender on Tourette Syndrome Beyond Adolescence

Although boys are disproportionately affected by tics in Tourette syndrome (TS), this gender bias is attenuated in adulthood and a recent study has suggested that women may experience greater functional interference from tics than men. The authors assessed the gender distribution of adults in a tertiary University-based TS clinic population and the relative influence of gender and other variables on adult tic severity (YGTSS score) and psychosocial functioning (GAF score). We also determined retrospectively the influence of gender on change in global tic severity and overall TS impairment (YGTSS) since adolescence. Females were over-represented in relation to previously published epidemiologic surveys of both TS children and adults. Female gender was associated with a greater likelihood of tic worsening as opposed to tic improvement in adulthood; a greater likelihood of expansion as opposed to contraction of motor tic distribution; and with increased current motor tic severity and tic-related impairment. However, gender explained only a small percentage of the variance of the YGTSS global severity score and none of the variance of the GAF scale score. Psychosocial functioning was influenced most strongly by tic severity but also by a variety of comorbid neuropsychiatric disorders.

Meta-analysis: Adulthood prevalence of Tourette syndrome

BACKGROUND

Tourette syndrome (TS) is estimated to have a prevalence of 0.30-0.77% in school aged children. Longitudinal studies suggest that roughly half-to-two-thirds of children with TS experience a substantial improvement in tic symptoms during adolescence. By contrast, few studies have examined adulthood prevalence of TS. Accurate prevalence estimates across the lifespan are needed to support regulatory and public health decisions.

METHODS

We searched PubMED and EMBASE for studies that examined the prevalence of TS in adults. We conducted a random-effects meta-analysis of logit event rates to estimate prevalence of TS across studies. Too few studies are available to conduct moderator analysis or examine publication bias. We also examined the risk ratio of TS prevalence in adults for males compared to females.

RESULTS

Three studies involving 2,356,485 participants were included. There were significant differences in TS adulthood prevalence estimates between studies ranging from 49 to 657 cases of TS per million adults. Overall prevalence of TS in adulthood was estimated to be 118 cases of TS per million adults (95%CI: 19-751 cases per million adults). There was a large amount of heterogeneity between studies (I² = 99%) that was likely related to differences in their methods of identification of TS cases. By contrast, the male:female ratio of risk of adulthood TS was similar between studies with a Risk Ratio = 2.33 (95% CI: 1.72-3.16).

CONCLUSION

Estimates of adulthood prevalence of TS are sparse and likely highly affected by differences in method of case identification. Diagnosis and diagnostic estimates of TS could be aided by including a requirement for impairment as well as potential remission criteria similar to other psychiatric conditions.

The impact of Tourette Syndrome in adults: results from the Tourette Syndrome impact survey

Chronic tic disorders (CTD) are characterized by motor and/or vocal tics. Existing data on the impact of tics in adulthood is limited by small, treatment-seeking samples or by data aggregated across adults and children. The current study explored the functional impact of tics in adults using a nationwide sample of 672 participants with a self-reported CTD. The impact of tics on physical, social, occupational/academic, and psychological functioning was assessed. Results suggested mild to moderate functional impairment and positive correlations between impairment and tic severity. Notable portions of the sample reported social or public avoidance and experiences of discrimination resulting from tics. Compared to previously reported population norms, participants had more psychological difficulties, greater disability, and lower quality of life. The current study suggests that CTDs can adversely impact functioning in adults and highlights the need for clinical interventions and systemic efforts to address tic-related impairments.

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.

Tic symptom profiles in subjects with Tourette Syndrome from two genetically isolated populations

BACKGROUND

Tourette Syndrome (TS) has a complex etiology and wide variability in phenotypic expression. Identifying underlying symptom patterns may be useful for etiological and outcome studies of TS.

METHODS

Lifetime tic and related symptom data were collected between 1996 and 2001 in 121 TS subjects from the Central Valley of Costa Rica and 133 TS subjects from the Ashkenazi Jewish (AS) population in the US. Subjects were grouped by tic symptoms using an agglomerative hierarchical cluster analysis. Cluster membership was tested for association with available ancillary information (age of onset, tic severity, comorbid disorders, medication treatment and family history).

RESULTS

Cluster analysis identified two distinct groups in each sample, those with predominantly simple tics (cluster 1), and those with multiple complex tics (cluster 2). Membership in cluster 2 was correlated with increased tic severity, global impairment, medication treatment, and presence of comorbid obsessive-compulsive symptoms in both samples, and with family history of tics, lower verbal IQ, earlier age of onset, and comorbid obsessive-compulsive disorder and attention-deficit/hyperactivity disorder in the AS sample.

CONCLUSIONS

This study provides evidence for consistent and reproducible symptom profiles in two independent TS study samples. These findings have implications for etiological studies of TS.

Childhood onset neuropsychiatric disorders in adult eating disorder patients. A pilot study

BACKGROUND

Autism spectrum disorders (ASD) have been suggested to be overrepresented in anorexia nervosa. This study aimed to explore the comorbidity of ASD and other childhood onset neuropsychiatric disorders (COND) [attention-deficit/hyperactivity disorder (AD/HD) and tic disorders] in a group of severe eating disorder (ED) patients.

METHOD

Thirty female ED patients from a specialist hospital clinic were examined on measures tapping into COND and personality disorders.

RESULTS

In our group of longstanding ED, 53% had at least one COND diagnosis; 23% had ASD, 17% had AD/HD, and 27% had a tic disorder.

CONCLUSIONS

These preliminary data suggest that COND may be common in patients with severe ED and should be kept in mind when treating these patients.

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

An epidemiological survey on Tourette syndrome (TS) in a developing country is relatively scarce. This study was conducted to investigate the prevalence and distribution of TS in children and juveniles aged 7-16 years in Wenzhou of P.R. China. A total of 9742 children and adolescents were included in this survey. Cross-sectional study with stratified-cluster sampling method was used. The prevalence of TS among school-age children was estimated to be an average of 0.43%. The ratio of male to female was 10.6 to 1 (0.74% for males and 0.07% for females). Pupils in the age range of 7-16 years are more likely to have comorbid disorders. The mean age at onset of TS was 7.7+/-2.7 years, with 45.2% of them at the age of 6-7. The rate of delayed diagnosis, misdiagnosis and misclassification of the syndrome were 78.6, 42.9 and 23.8%, respectively. This survey supports that TS is a common disease prevalent amongst children and juveniles in Wenzhou area of P.R. China, and its incidence was correlated with age and sex and often misdiagnosed and misclassified.

Reexamining Tic persistence and Tic-associated impairment in Tourette's Disorder: findings from a naturalistic follow-up study

The objective of this study was to assess tic persistence and tic-associated impairment in referred youth with Tourette's Disorder (TD). Subjects were 50 youth (ages 6-17 years) who met DSM-IV diagnostic criteria for TD, were referred to a specialized TD program, and were evaluated by clinical and structured diagnostic interview. Tic severity and impairment was measured using the Yale Global Tic Severity Scale. The total tic score at or above minimal range defined tic persistence, and a TD impairment score at or above moderate range defined tic-associated impairment. Results were assessed during administration of the Kiddie-Schedule for Affective Disorders and Schizophrenia for School-Age Children-Epidemiological Version. Mean age of onset of TD was 5.1 +/- 2.3 years, and mean illness duration was 5.6 +/- 3.2 years. At baseline, 88% of subjects met threshold criteria for at least mild tics, but only 30% met criteria for tic-associated impairment. At 2-year follow-up, 82% of these subjects met criteria for tic persistence (NS change from baseline), but only 14% met criteria for TD-associated impairment (p < .04 change from baseline). Although tics followed a persistent course in the majority of youth with TD, they were infrequently associated with impairment. There was a significant reduction in the proportion of youth with TD impairment from baseline to follow-up. These results support the view that TD is a persistent disorder, but suggest a dissociation between tic persistence and tic-associated dysfunction.

Tourette's syndrome in Taiwan: an epidemiological study of tic disorders in an elementary school at Taipei County

We have done an epidemiological study in an elementary school with 2000 Taiwanese children aged from 6 to 12 years, and found 11 of them with Tourette's syndrome. The prevalence rate of Tourette's syndrome was around 0.56%. The ratio of male to female was 9 to 2. The comorbid rate of attention-deficit/hyperactivity disorder was 36%, self-injurious behaviors 27%, and obsessive-compulsive behaviors 18%. The familial rate of Tourette's syndrome was 27%. We also found that another 98 children had transient tic disorders. For 73% of patients with mild tics, understanding and acceptance from family, teachers, and friends are the most important things. When tics are so severe that medication is necessary, haloperidol is no longer the first or only choice. We tried clonidine, atypical neuroleptics such as risperidone or olanzapine, or pergolide. The first support group was established in 1999 for children with tics in Taiwan and transformed to Taiwan Tourette Family association in June 2001 to provide further service for Tourette's syndrome.

Tics and problem behaviors in schoolchildren: prevalence, characterization, and associations

OBJECTIVE

Tic disorders are the most common movement disorder diagnosed in children and have symptoms that fluctuate in frequency and intensity over time. We conducted an 8-month longitudinal observational study to determine the variations in frequency of motor tics and associated problem behaviors.

METHODS

A total of 553 children, kindergarten through sixth grade, were observed monthly from November 1999 to June 2000 by 3 raters. Motor tics were recorded by location and rated for severity as none (0), mild (1), moderate (2), or severe (3). Problem behaviors were rated as absent (0), subclinical (1), or clinical (2) in each of 6 categories: disruptive, hyperactive, impulsive, aggressive, anxious, and distracted.

RESULTS

The monthly point prevalence of motor tics ranged from 3.2% to 9.6%, with an overall frequency of 24.4%. The monthly point prevalence of problem behaviors ranged from 2.6% to 11.0%, with an overall frequency of 25.7%. The incidence of motor tics and problem behaviors was significantly higher during the winter months of November through February, compared with the spring months of March through June (motor tics: z = 4.97; problem behaviors: z = 3.79). Motor tics were observed in 2 distinct patterns (isolated and persistent), which varied by the number of months present, gender ratio of affected children, severity of tic symptoms, and association with problem behaviors.

CONCLUSIONS

Motor tics and problem behaviors are frequent occurrences among schoolchildren and seem to occur more frequently during the winter months. For most children, the tics were mild, observed on only 1 occasion, and were not accompanied by problem behaviors.

Tics and its disorders

Tourette syndrome (TS) is familial neuropsychiatric disorder that is characterized by motor and phonic tics that begin in childhood. Once thought of as a rare and debilitating disorder, in the last decade new scientific knowledge suggests that TS and related tic disorders are more common and less debilitating for the majority of individuals. Evidence points toward a spectrum of TS symptomatology that extends beyond the tics disorder to probably include obsessive-compulsive disorder, attention deficit hyperactivity disorder, and mood disorders. Tourette syndrome and its differential diagnosis are discussed in this article with a focus on new developments in classification, etiology, epidemiology, genetics, pathophysiology, and clinical management.

Sex steroids and human behavior: implications for developmental psychopathology

In a variety of mammalian species, prenatal androgens organize brain structures and functions that are later activated by steroid hormones in postnatal life. In humans, studies of individuals with typical and atypical development suggest that sex differences in reproductive and nonreproductive behavior derive in part from similar prenatal and postnatal steroid effects on brain development. This paper provides a summary of research investigating hormonal influences on human behavior and describes how sex differences in the prevalences and natural histories of developmental psychopathologies may be consistent with these steroid effects. An association between patterns of sexual differentiation and specific forms of psychopathology suggests novel avenues for assessing the effects of sex steroids on brain structure and function, which may in turn improve our understanding of typical and atypical development in women and men.

Lamotrigine-induced tic disorder: report of five pediatric cases

PURPOSE

To describe the clinical spectrum of lamotrigine (LTG)-induced tics (an uncommon side effect) in children.

METHODS

Retrospective analysis of patients from our hospital-based practice who developed tics while on LTG. Data obtained from medical records, interviews with parents, video-EEGs, and homemade videotapes.

RESULTS

Three males and two females (range, 2.5-12 years; mean, 6.9 years) developed a movement disorder within the first 10 months of therapy (maintenance doses, 4-17 mg/kg/day). Four patients exhibited simple motor tics; one patient experienced mostly vocal (i.e., gasping sounds) tics. Laryngoscopic evaluation of one 2.5-year-old with repetitive gasping sounds was normal. In three cases, tics resolved completely within 1 month of drug cessation; tics recurred in two of these patients after reintroduction of LTG. A fourth patient experienced gradual improvement after stopping LTG over 4 months; the fifth patient's simple motor tics improved spontaneously with a reduction in medication. None of the patients had clinical features of a neurodegenerative disorder, and none met diagnostic criteria for Tourette syndrome. Two patients, however, had a diagnosis of acquired epileptic aphasia syndrome, and one patient had nonprogressive expressive and receptive language dysfunction. A fourth patient had global static encephalopathy, and the fifth patient had only attentional problems. In all patients, tics were not associated with ictal EEG changes.

CONCLUSIONS

LTG may infrequently induce simple motor tics, vocal tics, or both. Patients with severe language dysfunction may be particularly susceptible to this uncommon side effect. Further studies are necessary to clarify the population at risk.

Adult onset tic disorders

BACKGROUND

Tic disorders presenting during adulthood have infrequently been described in the medical literature. Most reports depict adult onset secondary tic disorders caused by trauma, encephalitis, and other acquired conditions. Only rare reports describe idiopathic adult onset tic disorders, and most of these cases represent recurrent childhood tic disorders.

OBJECTIVE

To describe a large series of patients with tic disorders presenting during adulthood, to compare clinical characteristics between groups of patients, and to call attention to this potentially disabling and underrecognised neurological disorder.

METHODS

Using a computerised database, all patients with tic disorders who presented between 1988 and 1998 to the movement disorders clinic at Columbia-Presbyterian Medical Center after the age of 21 were identified. Patients' charts were retrospectively reviewed for demographic information, age of onset of tics, tic phenomenology, distribution, the presence of premonitory sensory symptoms and tic suppressibility, family history, and associated psychiatric features. These patients' videotapes were reviewed for diagnostic confirmation and information was obtained about disability, course, and response to treatment in a structured follow up interview.

RESULTS

Of 411 patients with tic disorders in the database, 22 patients presented for the first time with tic disorders after the age of 21. In nine patients, detailed questioning disclosed a history of previous childhood transient tic disorder, but in 13 patients, the adult onset tic disorder was new. Among the new onset cases, six patients developed tics in relation to an external trigger, and could be considered to have secondary tic disorders. The remaining patients had idiopathic tic disorders. Comparing adult patients with recurrent childhood tics and those with new onset adult tics, the appearance of the tic disorder, the course and prognosis, the family history of tic disorder, and the prevalence of obsessive-compulsive disorder were found to be similar. Adults with new onset tics were more likely to have a symptomatic or secondary tic disorder, which in this series was caused by infection, trauma, cocaine use, and neuroleptic exposure.

CONCLUSIONS

Adult onset tic disorders represent an underrecognised condition that is more common than generally appreciated or reported. The clinical characteristics of adults newly presenting to a movement disorder clinic with tic disorders are reviewed, analysed, and discussed in detail. Clinical evidence supports the concept that tic disorders in adults are part of a range that includes childhood onset tic disorders and Tourette's syndrome.

Peek-a-boo fragile site at 16d associated with Tourette syndrome, bipolar disorder, autistic disorder, and mental retardation

Five patients with a fragile site at 16q22-23 and neuropsychiatric disorders are reported. Three of five had Tourette disorder, three had mental retardation, two had bipolar disorder, and one had autistic disorder. During our attempts to study the fragile sites in more detail we were unable to reproduce the fragile sites found several years earlier. The potential relationship between the fragile sites and the neuropsychiatric disorders in these patients is discussed. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:69-73, 2000.

An unusual presentation of Tourette's syndrome

STUDY OBJECTIVE

To report an unusual complex motor tic as the presenting symptom in a patient diagnosed with Tourette's syndrome.

METHODS

This case report was compiled via interview with a 9-year-old white female who presented to the private gynecologic practice of the senior author. Additional history was gained from the patient's mother and follow up information was obtained from written and verbal communication with neurology colleagues.

MAIN OUTCOME MEASURES

Referral to neurology. Diagnosis of persistent perineal touching.

RESULTS

Diagnosis of Tourette's syndrome.

CONCLUSION

In young patients with nonspecific vulval symptoms, Tourette's syndrome should be considered in the differential diagnosis particularly if persistent self touching is a feature of the complaint. Referral to a physician experienced with the syndrome is important since the diagnosis is made on the basis of the clinical symptoms and signs.

Complex segregation analysis for obsessive compulsive disorder and related disorders

Complex segregation analysis was applied to a sample of 107 Italian families with probands with obsessive compulsive disorder (OCD), using regressive logistic models to test for possible models of genetic transmission. We used two different phenotypic definitions of affection: 1) OCD; and 2) OCD plus Tourette's syndrome/chronic motor tics (CMT). Because of the potential relationship between OCD, Tourette's syndrome (TS), and other tic disorders, we considered these diagnoses to be determined by the same liability in subsequent steps of the analysis. For the 107 OCD families, the best fit was a dominant model of transmission (with a higher penetrance for females). When the phenotype boundaries were widened (OCD + CMT + TS), an unrestricted model of transmission became the best fit. We concluded that additional data are needed to support the hypothesis that Tourette's syndrome and OCD share a common etiology: on the basis of clinical and epidemiological considerations, the OCD phenotype probably presents a higher level of heterogeneity than the TS phenotype, and it could be regulated through different etiologic pathways.

A double-blind, placebo-controlled, crossover trial of an antiandrogen in the treatment of Tourette's syndrome

The objective of this study was to document the effects of androgen receptor blockade on tic and obsessive-compulsive symptoms in Tourette's syndrome (TS) patients. Thirteen adult TS subjects, 10 men and 3 women, completed 3 weeks of each phase of a double-blind, placebo-controlled, crossover trial of flutamide, a selective androgen receptor antagonist. Symptom severity ratings and hormone levels were obtained at each of the trial's six clinic visits. Flutamide was well-tolerated and produced a significant reduction in motor but not phonic tic symptom severity. It modestly improved symptoms of obsessive-compulsive disorder in the men who had this disorder. Changes in hormone levels during flutamide administration provided evidence for the existence of physiologic mechanisms that compensate for the blocking of the androgen receptor. The therapeutic effects of flutamide are modest in magnitude and they seem to be short-lived, possibly because of physiologic compensation for androgen receptor blockade. Given the potentially serious side effects of flutamide, the use of this agent in the treatment of tics should be reserved for patients who have relatively debilitating symptoms. The therapeutic and endocrine findings may have implications for understanding the sex differences in TS prevalence and the sex-specific variability in the phenotypic expression of the putative TS vulnerability genes.

Course of tic severity in Tourette syndrome: the first two decades

OBJECTIVE

Prevalence studies indicate a 10-fold higher rate of Tourette syndrome (TS) among children compared with adults. The purpose of this investigation was to examine the course of tic severity during the first 2 decades of life.

METHOD

A birth-year cohort of 42 TS patients followed at the Yale Child Study Center was recontacted an average of 7.3 years after their initial clinical evaluation. Data concerning the onset and course of tic severity until 18 years of age were available on 36 TS patients. A variety of statistical techniques were used to model aspects of the temporal patterning of tic severity.

RESULTS

Mean (SD) tic onset at 5.6 (2. 3) years of age was followed by a progressive pattern of tic worsening. On average, the most severe period of tic severity occurred at 10.0 (2.4) years of age. In eight cases (22%), the frequency and forcefulness of the tics reached a severe level during the worst-ever period such that functioning in school was impossible or in serious jeopardy. In almost every case this period was followed by a steady decline in tic severity. By 18 years of age nearly half of the cohort was virtually tic-free. The onset of puberty was not associated with either the timing or severity of tics.

CONCLUSIONS

A majority of TS patients displayed a consistent time course of tic severity. This consistency can be accurately modeled mathematically and may reflect normal neurobiological processes. Determination of the model parameters that describe each patient's course of tic severity may be of prognostic value and assist in the identification of factors that differentially influence the course of tic severity.

Tic disorders

The picture that emerges is one of complex behavioral phenotypes that alter over the course of CNS development. While many cases are mild and may not come to medical attention, others are chronic and disabling. The aim of this article is to provide an overview of recent progress in understanding phenomenology, epidemiology, genetics, neurobiology, and treatment of tic disorders.

The course and prognosis of Tourette syndrome

The view of Tourette syndrome as a lifelong disorder, once held as a certainty, has changed considerably in the past two decades. It is now known that in the majority of cases, tics will ebb in severity and will no longer be problematic in the adult years. This discovery, however, has been accompanied by the realization that Tourette syndrome is a far more complex disorder than was originally discerned and that it has many unanswered questions.

Epidemiology of Tourette syndrome

The epidemiology of Tourette syndrome is difficult to characterize because there is no definitive diagnosis. Symptom intensity and frequency decrease with age and in social situations, and affected individuals are often unaware of their tics. This chapter reviews and summarizes current data on the prevalence, distribution, and risk factors for Tourette syndrome.

Tourette disorder: a cross-cultural review

Tourette's disorder (TD) is a complex disorder of motor and vocal tics starting in childhood or adolescence. Although the disorder has been researched extensively in North America and Europe, clinical features and associated conditions of TD are less well known in other cultures. The English-language literature relating to TD was searched for cross-cultural case reports, clinical investigations, and epidemiological studies, and the subsequent database was analyzed. The clinical characteristics of TD displayed a strong similarity across cultures. Demography, family history, clinical features, associated conditions, comorbidity, and treatment outcome were essentially the same in the various cultures investigated. The disorder appears world-wide, has similar clinical characteristics, and most likely has an underlying biological and genetic basis.

Tourette's syndrome in the year 2000

OBJECTIVE

To examine the current status of knowledge of Tourette's syndrome (TS) and to highlight those areas of research that are most likely to have the most significant advances in the next few years into the 21st century.

METHOD

Index Medicus was consulted from its beginning in 1885 until 1964 (inclusive), looking initially under the title 'tics' and subsequently under 'Tourette's Disorder'. From 1965 and the advent of MEDLINE, a search was performed looking for 'Tourette's'. A chronological examination of TS in the medical literature is presented. Some issues surrounding Huntington's Disease (HD) research are pertinent to TS and may serve as a guide in the future direction of TS research; these issues have been identified and illustrated in the context of TS. Where relevant, other medical disorders are also commented on.

RESULTS

There has been a steady increase in the volume of TS literature since 1885, with a marked increase since 1980, changing in focus from a psychological to a neurobiological viewpoint. Current areas of interest include genetics, comorbid psychopathologies, neuroimaging, treatments, epidemiology and educational considerations. Issues raised by HD and other movement disorders such as Parkinson's Disease (PD) are predictive testing, gene therapy and neural transplants.

CONCLUSIONS

The year 2000 is likely to herald a significant increase in our knowledge of the genetics and neuroimaging of TS, with new developments in therapy. A broadening of awareness of TS among health workers and teachers in particular is likely to increase the number of diagnosed patients and, hence, new challenges will be posed to existing resources for health and educational provision.

Executive functions and developmental psychopathology

In this paper, we consider the domain of executive functions (EFs) and their possible role in developmental psychopathologies. We first consider general theoretical and measurement issues involved in studying EFs and then review studies of EFs in four developmental psychopathologies: attention deficit hyperactivity disorder (ADHD), conduct disorder (CD), autism, and Tourette syndrome (TS). Our review reveals that EF deficits are consistently found in both ADHD and autism but not in CD (without ADHD) or in TS. Moreover, both the severity and profile of EF deficits appears to differ across ADHD and autism. Molar EF deficits are more severe in the latter than the former. In the few studies of more specific EF tasks, there are impairments in motor inhibition in ADHD but not in autism, whereas there are impairments in verbal working memory in autism but not ADHD. We close with a discussion of implications for future research.

Second messenger systems in Tourette's syndrome

Abnormalities within second messenger systems have been hypothesized as the underlying pathophysiologic mechanism in a variety of neuropsychiatric disorders. In the Gilles de la Tourette syndrome (TS) prior studies have shown that the concentration of adenosine 3',5'-monophosphate (cAMP) is reduced in cortical and putamen brain regions. In this study, postmortem cortical tissues from 4 adults (mean age 59.5 years) with the lifetime diagnosis of TS and 5 controls (mean age 63.8 years) were analyzed for functional activities within the cAMP and phosphoinositide systems. In addition, plasma cAMP was quantified in children with TS (n = 33) and controls (n = 17). In frontal (A4, A6) and occipital (A17) cortical tissues there were no significant differences for adenylyl cyclase activity whether assayed under basal conditions or after stimulation with GTP gamma S (a non-hydrolyzable GTP analog), forskolin (a selective enzyme stimulator), or (-)-isoproterenol (a beta-adrenergic agonist). D2 receptor activation (quinpirole) and assessment of the inhibitory guanine nucleotide protein also showed no significant alterations in TS samples. Activity of cAMP phosphodiesterase was increased insignificantly in A4 and A17 TS brain regions. Plasma concentrations of cAMP in plasma were similar in children with TS (135.4 +/- 8.3 pmol/ml) and controls (132.6 +/- 7.9 pmol/ml). Postmortem membrane receptor binding for markers within the phosphoinositide (PI) system showed that TS samples had increased [3H]phorbol ester binding to protein kinase C sites in area A17, but normal binding in A4. In contrast, [3H] inositol 1,4,5-triphosphate binding to IP3 receptors showed no significant changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Developmental psychopathology and neurobiology of Tourette's syndrome

OBJECTIVE

The authors present a model of the developmental psychopathology and neurobiology of Tourette's syndrome that provides a framework for ongoing research and treatment.

METHOD

The model is based on clinical experience and a selective review of relevant scientific literature.

RESULTS

During the past decade, Tourette's syndrome and related conditions have emerged as model disorders to study the interplay of genetic, neurobiological, psychological, and environmental factors during development. Although prevention and treatment are paramount, the effectiveness of these interventions depends on the quality and extent of our knowledge. Programmatic research combined with sustained clinical care has led to advances in our knowledge of the natural history of these disorders over the course of development and glimpses of the pathophysiologic and psychopathological mechanisms that mediate their expression in vulnerable persons.

CONCLUSIONS

In the future, we expect that our understanding will extend from the molecular level of how specific genes and epigenetic factors confer and mediate vulnerability to an understanding of why certain symptoms emerge when they do in the course of central nervous system development.

Tourette's syndrome, Part I: Definition and diagnosis

Tourette's syndrome (TS) is a neuropsychiatric disorder characterized by a changing repertoire of motor and phonic tics that typically begin in childhood and exhibit a fluctuating course. Obsessive-compulsive symptoms and problems of inattention, overactivity, and impulsiveness are present in some cases. Historically, TS has been viewed as a severe disorder. However, data from epidemiologic and family-genetic studies indicate that it shows a wide range of severity. This article, the first of two parts, examines the current notions concerning the origin, pathophysiology, and diagnosis of TS. The second article will present three cases and describe contemporary approaches to treatment.

Gilles de la Tourette syndrome: a neuropsychiatric disorder

Gilles de la Tourette Syndrome is a neuropsychiatric disorder which manifests with neurological psychological and psychiatric symptoms. Understanding of this complex disorder has grown rapidly in the past 25 years. This paper reviews the current knowledge of biological and psychological factors which interact to produce a variable yet clearly recognisable syndrome. New directions for research are explored. Current literature suggests that despite many gains, much remains to be learned about this disorder.

Perinatal factors in the expression of Tourette's syndrome: an exploratory study

The search for nongenetic factors that mediate the expression of a genetic vulnerability to Tourette's syndrome (TS) is an important undertaking that may provide valuable clues concerning the pathophysiology of this disorder as well as potential treatment approaches. In a direct interview study, the perinatal experiences of 31 TS patients were compiled in an effort to identify risk factors associated with tic severity. Severity of maternal life stress during pregnancy, gender of the child, and severe nausea and/or vomiting during the first trimester were found to be significantly associated with current tic severity. Future longitudinal studies of "at-risk" children are needed to confirm these findings. Set in the context of a known chromosomal site for the TS diathesis, such studies will permit the identification and quantification of risk and protective factors in the expression of TS and further develop TS as a model neuropsychiatric disorder for the study of gene-environment interactions.

The Gilles de la Tourette syndrome: the current status

The Gilles de la Tourette Syndrome is a movement disorder characterised by both motor and vocal (phonic) tics. It was once thought to be rare, and the literature until the 1970s consisted predominantly of case reports, both highlighting the fascinating clinical manifestations and speculating as to their aetiology. Many areas of GTS are under investigation, including the neurology, psychopathology, neurophysiology, biochemistry, and genetics. This review briefly considers early descriptions of GTS as well as current research, highlighting the areas of agreement and controversy.

Tourette disorder in North Dakota

This paper describes the symptom profiles of a large group of patients with Gilles de la Tourette disorder (TD). In Part one we report the results of a questionnaire study of patients in North Dakota with TD. The data suggest that TD patients have high rates of academic and social problems. Obsessive-compulsive symptomatology is quite high in this population. This report is unique in that these results are reported using an available data base to allow for pooling of future research in TD patients in other settings. In Part two of this paper we discuss important findings from our clinic population of 130 TD patients.

Family data support a dominant major gene for Tourette syndrome

A dominant major gene was supported by analyses of 50 large extended Tourette syndrome (TS) pedigrees and by a subset of families defined by proband's clinical response to the neuroleptic drug haloperidol. Relatives were defined as affected if they ever had tics or TS. Assuming a nearly even sex ratio for TS and related symptoms resulted in the best fit of the genetic model to observed rates in families.