Tourette syndrome and chronic tic disorder are associated with lower socio-economic status: findings from the Avon Longitudinal Study of Parents and Children cohort

Factors linked to prognosis in children with provisional tic disorder: a prospective cohort study

The purpose of the present study was to estimate the factors linked to the prognosis of children with provisional tic disorder (PTD). We conducted a prospective cohort study enrolled children with PTD who were subsequently followed-up at three-month intervals for 1 year post-enrolment. A total of 259 PTD patients were included in the final analysis. At the end of the follow-up period, 77 (30%) of the patients had achieved clinical remission. Result of the LASSO logistic regression analysis revealed that a disease duration >3 months (OR=4.20, 95% CI 1.20-14.73), moderate/severe tic severity (OR=5.57, 95% CI 2.26-13.76), and comorbid behavioral problems (OR=2.78, 95% CI 1.15-6.69) were significant factors linked to remission in the PTD patients. The path analysis model showed that comorbid behavioral problems and recurrence partially mediated the association between tic severity and remission, with a mediating effect of 37%. Conclusions: We have identified several significant factors linked to prognosis in children with PTD, including comorbid behavioral problems and recurrence, which were found to be important mediators. These findings provide new insights for the clinical management of patients with PTD.

The Challenge of Examining Social Determinants of Health in People Living With Tourette Syndrome

BACKGROUND

To examine the association between race, ethnicity, and parental educational attainment on tic-related outcomes among Tourette Syndrome (TS) participants in the Tourette Association of America International Consortium for Genetics (TAAICG) database.

METHODS

723 participants in the TAAICG dataset aged ≤21 years were included. The relationships between tic-related outcomes and race and ethnicity were examined using linear and logistic regressions. Parametric and nonparametric tests were performed to examine the association between parental educational attainment and tic-related outcomes.

RESULTS

Race and ethnicity were collapsed as non-Hispanic white (N=566, 88.0%) versus Other (N=77, 12.0%). Tic symptom onset was earlier by 1.1 years (P < 0.0001) and TS diagnosis age was earlier by 0.9 years (P = 0.0045) in the Other group (versus non-Hispanic white). Sex and parental education as covariates did not contribute to the differences observed in TS diagnosis age. There were no significant group differences observed across the tic-related outcomes in parental education variable.

CONCLUSIONS

Our study was limited by the low number of nonwhite or Hispanic individuals in the cohort. Racial and ethnic minoritized groups experienced an earlier age of TS diagnosis than non-Hispanic white individuals. Tic severity did not differ between the two groups, and parental educational attainment did not affect tic-related outcomes. There remain significant disparities and gaps in knowledge regarding TS and associated comorbid conditions. Our study suggests the need for more proactive steps to engage individuals with tic disorders from all racial and ethnic minoritized groups to participate in research studies.

Incidence trend and epidemiology of tic disorders among youths and adults in Korea from 2003 to 2020: A national population-based study

Tic disorder is a highly prevalent neurodevelopmental disorder; however, research on its incidence trends is still rare. We aimed to investigate its annual incidence rates and the characteristics of incident cases in the general Korean population using data from the National Health Insurance Service-National Health Information Database as a proxy measurement for true incidence in the community. The total number of incident cases and incidence rates of tic disorders from 2003 to 2020 were compared between youths and adults. Both the number of incident cases and the annual incidence rates of tic disorders significantly increased from 2003 to 2020. The overall increasing trend in the incidence rates was significantly greater in youths than in adults; however, the incidence rates in adults showed a relatively recent increase. The male predominance regarding the newly diagnosed case number in youths was no longer observed in adults. Tic disorders occurred more commonly in the low-income group than in the high-income group. Neurodevelopmental comorbidities in youths and mood or anxiety disorders and schizophrenia in adults were more frequently observed. Antipsychotic medication adherence was higher in youths than in adults. Efforts are required to raise awareness and promote expert education for adult patients with tic disorders.

An Update on the Diagnosis and Management of Tic Disorders

Tic disorders (TDs) are a group of common neuropsychiatric disorders of childhood and adolescence. TDs may impact the physical, emotional, and social well-being of the affected person. In this review, we present an update on the clinical manifestations, pathophysiology, diagnosis, and treatment of TDs. We searched the PubMed database for articles on tics and Tourette syndrome. More than 400 articles were reviewed, of which 141 are included in this review. TDs are more prevalent in children than in adults and in males than in females. It may result from a complex interaction between various genetic, environmental, and immunological factors. Dysregulation in the cortico-striato-pallido-thalamo-cortical network is the most plausible pathophysiology resulting in tics. TD is a clinical diagnosis based on clinical features and findings on neurological examination, especially the identification of tic phenomenology. In addition to tics, TD patients may have sensory features, including premonitory urge; enhanced and persistent sensitivity to non-noxious external or internal stimuli; and behavioral manifestations, including attention deficit hyperactivity disorders, obsessive-compulsive disorders, and autism spectrum disorders. Clinical findings of hyperkinetic movements that usually mimic tics have been compared and contrasted with those of TD. Patients with TD may not require specific treatment if tics are not distressing. Psychoeducation and supportive therapy can help reduce tics when combined with medication. Dispelling myths and promoting acceptance are important to improve patient outcomes. Using European, Canadian, and American guidelines, the treatment of TD, including behavioral therapy, medical therapy, and emerging/experimental therapy, has been discussed.

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

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

Recent progress on Tourette syndrome

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

Maternal immune activation and neuroinflammation in human neurodevelopmental disorders

Maternal health during pregnancy plays a major role in shaping health and disease risks in the offspring. The maternal immune activation hypothesis proposes that inflammatory perturbations in utero can affect fetal neurodevelopment, and evidence from human epidemiological studies supports an association between maternal inflammation during pregnancy and offspring neurodevelopmental disorders (NDDs). Diverse maternal inflammatory factors, including obesity, asthma, autoimmune disease, infection and psychosocial stress, are associated with an increased risk of NDDs in the offspring. In addition to inflammation, epigenetic factors are increasingly recognized to operate at the gene-environment interface during NDD pathogenesis. For example, integrated brain transcriptome and epigenetic analyses of individuals with NDDs demonstrate convergent dysregulated immune pathways. In this Review, we focus on the emerging human evidence for an association between maternal immune activation and childhood NDDs, including autism spectrum disorder, attention-deficit/hyperactivity disorder and Tourette syndrome. We refer to established pathophysiological concepts in animal models, including immune signalling across the placenta, epigenetic 'priming' of offspring microglia and postnatal immune-brain crosstalk. The increasing incidence of NDDs has created an urgent need to mitigate the risk and severity of these conditions through both preventive strategies in pregnancy and novel postnatal therapies targeting disease mechanisms.

Maternal acute and chronic inflammation in pregnancy is associated with common neurodevelopmental disorders: a systematic review

Inflammation is increasingly recognized as a cause or consequence of common problems of humanity including obesity, stress, depression, pollution and disease states such as autoimmunity, asthma, and infection. Maternal immune activation (MIA), triggered by both acute and systemic chronic inflammation, is hypothesized to be one of the mechanisms implicated in the pathogenesis of neurodevelopmental disorders (NDD). Although there is substantial preclinical evidence to support the MIA hypothesis, the human evidence is disparate. We performed a systematic review on human studies examining associations between maternal inflammatory states and offspring NDDs (autism spectrum disorder- ASD, attention deficit hyperactivity disorder-ADHD, Tourette syndrome-TS). 32 meta-analyses and 26 additional individual studies were identified. Maternal states associated with ASD include obesity, gestational diabetes mellitus, pre-eclampsia, pollution, stress, depression, autoimmune diseases, and infection. Maternal states associated with ADHD include obesity, pre-eclampsia, smoking, low socioeconomic status (SES), stress, autoimmune disease, and asthma. Maternal states associated with TS include low SES, depression, and autoimmune diseases. Diverse maternal inflammatory states in pregnancy are associated with common offspring NDDs. Given the increased prevalence of NDDs, there is urgent need to explore relative and cumulative maternal risk factors and disease mechanisms. Defining preventable risk factors in high-risk pregnancies could mitigate the expression and severity of NDDs.

Longitudinal Bidirectional Relationships Between Maternal Depressive/Anxious Symptoms and Children's Tic Frequency in Early Adolescence

Background: Previous studies have revealed an association between maternal depressive/anxious symptoms and children's tics. However, the longitudinal relationships between these symptoms remain unclear. We examined the longitudinal relationships between maternal depressive/anxious symptoms and children's tic frequency in early adolescence with a population-based sample. Methods: The participants consisted of 3,171 children and their mothers from the Tokyo Teen Cohort (TTC) study, a population-representative longitudinal study that was launched in Tokyo in 2012. Maternal depressive/anxious symptoms and children's tics were examined using self-report questionnaires at the ages of 10 (time 1, T1) and 12 (time 2, T2). A cross-lagged model was used to explore the relationships between maternal depressive/anxious symptoms and children's tic frequency. Results: Higher levels of maternal depressive/anxious symptoms at T1 were related to an increased children's tic frequency at T2 (β = 0.06, p < 0.001). Furthermore, more frequent children's tics at T1 were positively related to maternal depressive/anxious symptoms at T2 (β = 0.06, p < 0.001). Conclusions: These findings suggest a longitudinal bidirectional relationship between maternal depressive/anxious symptoms and children's tic frequency in early adolescence that may exacerbate each other over time and possibly create a vicious cycle. When an early adolescent has tics, it might be important to identify and treat related maternal depressive/anxious symptoms.

The association between tic medication therapy and psychiatric comorbidities among patients with Tourette syndrome: A national population-based study in Taiwan

BACKGROUND

Tourette syndrome (TS) is often comorbid with attention deficit hyperactivity disorder, obsessive-compulsive disorder, and depression. Medications are the main treatment for TS. Relationships between TS medication therapy and psychiatric comorbidities remain unclear. This study explored the impacts of TS medication on the risk of psychiatric comorbidities using a nationally representative sample of TS in Taiwan.

METHODS

Data from National Health Insurance Research Database in Taiwan was used to identify 997,213 children and adolescents aged 6-18 years who had received a diagnosis of TS based on ICD-9-CM codes in 2000-2010. Cox's proportional hazard regression analysis was conducted to estimate the risk of comorbidities among subjects with and without tic medication therapy.

RESULTS

We found that in TS patients, a lower risk of psychiatric comorbidities occurred in the tic medication therapy group (p = 0.012) and the crude hazard ratio (HR) was 0.6 (95% confidence interval (CI) = 0.4-0.8, p < 0.001). After adjusting for potential confounders of gender, age, income, level of care, department visited, brain injury, and the number of suicide attempts, the risk of comorbidities was still significantly lower in the tic medication therapy group (adjusted HR = 0.5, 95% CI = 0.3-0.6, p < 0.001).

DISCUSSION

One limitation was that we did not include all mediations used to treat psychiatric comorbidities among TS patients. This study found the effectiveness of TS medications on improving psychiatric comorbidities.

CONCLUSIONS

Compared to those without medication, medication therapy appears to have a benefit of decreasing the risk of psychiatric comorbidities. Strategies to improve medication regimens should be considered in clinical settings.

Population-Based Epidemiology of Pediatric Patients with Treated Tic Disorders from Real-World Evidence in Korea

Objectives: Although tic disorder (TD) is a common mental disorder in children and adolescents, epidemiological data based on real-world evidence (RWE) are insufficient. Using RWE, this study sought to examine the prevalence of treated TD, use of medical utilization, and use of prescription drugs among patients with TD with respect to TD type and comorbid psychiatric illness. Methods: We performed a retrospective cross-sectional study. Using the Korean Health Insurance Review and Assessment Service Pediatric Patient Sample data from 2009 to 2016, we analyzed 20,599 patients with TD (Korean Standard Classification of Diseases-6/7 code: F95.x) aged 2-19 years. Results: The annual average TD prevalence was 2.6/1000 population (95% confidence interval, 2.3-2.8/1000). Between 2009 and 2016, a slight increase in TD prevalence was observed from 1.9 to 2.9/1000 population. The TD prevalence rate in male patients was four times higher than that in female patients. Differences were observed in health care utilization and drug prescription types between patients with Tourette syndrome and chronic or transient TD. In addition, more than half of patients with TD had comorbid psychiatric disorders, and one-third of patients with TD had attention-deficit/hyperactivity disorder (ADHD). Patients with TD without comorbidities were frequently prescribed aripiprazole, while patients with TD and comorbid ADHD were frequently prescribed atomoxetine, methylphenidate, risperidone, and aripiprazole. Conclusion: This study described the epidemiological characteristics of TD based on recent RWE from Korea, and its findings can help establish future TD evidence-based clinical guidelines and related policies.

Health-related quality of life, anxiety and depression in parents of adolescents with Gilles de la Tourette syndrome: a controlled study

Our objectives were to assess health-related quality of life (HRQoL), anxiety, depression of Gilles de la Tourette syndrome (GTS) adolescents' parents compared to controls; to assess GTS adolescents' HRQoL compared to controls; to investigate which parental and adolescent variables are associated with poorer parental HRQoL. The controlled study involved GTS outpatients and their parents, adolescent healthy controls matched for gender and age and their parents. Parents' HRQoL was assessed using SF-36 and WHOQOL-BREF; anxiety, depression using HADS. Adolescents' HRQoL was assessed by adolescents using VSP-A instrument and by their parents using VSP-P. A total of 75 GTS adolescents, 75 mothers, 63 fathers were compared to 75 control adolescents, 75 mothers, 62 fathers. GTS mothers had worse HRQoL than controls on 5 of the 8 SF-36 dimensions and 1 of the 4 WHOQOL-BREF dimensions, while GTS fathers had worse HRQoL on 2 of the WHOQOL-BREF dimensions. GTS mothers had poorer HRQoL than fathers. GTS mothers had more depression than control mothers and GTS fathers had more anxiety than control fathers. GTS adolescents had worse HRQoL than controls on 5 of the 9 VSP-A dimensions. Factors significantly related to parental HRQoL were anxiety, depression, GTS adolescents' HRQoL and, concerning mothers, behavioural and emotional adolescents' problems; concerning fathers, severity of vocal tics, duration since first symptoms. This study provides a better understanding of poorer HRQoL and psychiatric morbidity of GTS adolescents' parents. Clinicians should pay attention to their emotional well-being and HRQoL and be aware that mothers and fathers are differently affected.

Increased Risk of Tics in Children Infected with Enterovirus: A Nationwide Population-Based Study

OBJECTIVE

Both tics and enterovirus (EV) infections are common in children. The association between EV infections and tics has been seldom evaluated. The aim of this study was to evaluate the risk of diagnosed tics after EV infections in children.

METHODS

A nationwide retrospective cohort study was conducted to determine the risk of tics after EV infections by analyzing data from the National Health Insurance Research Database in Taiwan. Children aged < 18 years with EV infection during 2000 to 2007 were enrolled. For comparison, non-EV-infected children were randomly selected and matched with EV-infected children at a 1:1 ratio according to sex, age, urbanization level, parental occupation, and the year of EV infection. All patients were followed up until the diagnosis of tics, death, loss to follow-up, withdrawal from the insurance system, or December 31, 2008.

RESULTS

A total of 282,321 EV-infected and 282,317 non-EV-infected children were included in this study. The mean age was 2.39 years in both cohorts. The overall incidences of tics were 9.12 and 6.21 per 10,000 person-years in the EV-infected and non-EV-infected cohorts, respectively. Children with EV infection were significantly associated with an increased risk of tics compared with those without EV infection (adjusted hazard ratio, 1.38; 95% confidence interval, 1.27-1.5). Multivariable analyses showed that boys, children living in urbanized areas, children whose parents had white-collar jobs, and children with allergic rhinitis or bronchial asthma exhibited a significantly increased risk of tics.

CONCLUSION

This study revealed an increased risk of tics after EV infection in children.

Abating Mercury Exposure in Young Children Should Include Thimerosal-Free Vaccines

Pediatric immunization is essential to prevent, control and eradicate children`s infectious diseases. Newborns and infants in less developed countries have a concentrated schedule of Thimerosal-containing vaccines (TCVs); pregnant mothers are also immunized with TCVs. Metabolic changes during early development are demonstrably an important risk factor for ethylmercury (EtHg) effects on neurodevelopment, while exposure to Thimerosal sensitizes susceptible individuals to life-long contact dermatitis. Concerns regarding toxicity of Hg have moved rich nations to withdraw it from medicines and, in particular, Thimerosal from pediatric vaccines; it has been more than 20 years since rich countries started using Thimerosal-free vaccines. TCVs and Thimerosal-free vaccines show dissimilar profiles of adverse effects. Thimerosal-free vaccines have shown a decrease in contact dermatitis, while TCVs showed a significant association with increased risk of tic disorders; in some circumstances, EtHg in combination with other neurotoxic substances negatively impacted neurobehavioral tests. In studies that explored vaccines and risk of tics, Thimerosal was a necessary factor. However, when the binary exposure to organic Hg forms (TCV-EtHg and fish-MeHg) was considered, effects on neurobehavioral tests were inconsistent.

CONCLUSIONS

(a) The indiscriminate use of pediatric-TCVs in less developed countries carries an unjustifiable and excessive EtHg exposure with an unnecessary risk of neurotoxicity to the developing brain; (b) measurable benefits (of Thimerosal-free) and measurable risks of tic disorders have been associated with the (Thimerosal-containing) type of vaccine;

Heritability of tic disorders: a twin-family study

BACKGROUND

Genetic-epidemiological studies that estimate the contributions of genetic factors to variation in tic symptoms are scarce. We estimated the extent to which genetic and environmental influences contribute to tics, employing various phenotypic definitions ranging between mild and severe symptomatology, in a large population-based adult twin-family sample.

METHOD

In an extended twin-family design, we analysed lifetime tic data reported by adult mono- and dizygotic twins (n = 8323) and their family members (n = 7164; parents and siblings) from 7311 families in the Netherlands Twin Register. We measured tics by the abbreviated version of the Schedule for Tourette and Other Behavioral Syndromes. Heritability was estimated by genetic structural equation modeling for four tic disorder definitions: three dichotomous and one trichotomous phenotype, characterized by increasingly strictly defined criteria.

RESULTS

Prevalence rates of the different tic disorders in our sample varied between 0.3 and 4.5% depending on tic disorder definition. Tic frequencies decreased with increasing age. Heritability estimates varied between 0.25 and 0.37, depending on phenotypic definitions. None of the phenotypes showed evidence of assortative mating, effects of shared environment or non-additive genetic effects.

CONCLUSIONS

Heritabilities of mild and severe tic phenotypes were estimated to be moderate. Overlapping confidence intervals of the heritability estimates suggest overlapping genetic liabilities between the various tic phenotypes. The most lenient phenotype (defined only by tic characteristics, excluding criteria B, C and D of DSM-IV) rendered sufficiently reliable heritability estimates. These findings have implications in phenotypic definitions for future genetic studies.

Parental socioeconomic status and child intellectual functioning in a Norwegian sample

Socioeconomic status (SES) in childhood has been linked to cognitive function and future academic and occupational success in studies from several countries. However, previous Nordic studies have shown inconsistent results regarding the strength of this link. We therefore investigated the association between SES and cognitive functioning in a sample of 255 Norwegian children, including 151 typically developing children and 104 children with a psychiatric diagnosis. The third edition of the Wechsler Intelligence Scale for Children (WISC-III) to assess cognitive function was used. SES was defined from maternal and paternal education and family income of typically developing children and of a subsample of children with a psychiatric diagnosis. Multiple adjusted regression analyses were used to investigate the relation between SES and cognitive functioning. The analyses showed that SES explained a significant part of the variance of the full-scale WISC-III score and two WISC-III indices (Verbal Comprehension and Freedom from Distractibility). Overall, the strength of the relations was weaker than expected from reports from other non-Nordic countries. Parental education was the only significant individual predictor, suggesting that income was of minor importance as a predictor of cognitive functioning. Further studies should investigate how diverse political and socioeconomic contexts influence the relation between SES and cognitive functioning.

Pre- and perinatal complications in relation to Tourette syndrome and co-occurring obsessive-compulsive disorder and attention-deficit/hyperactivity disorder

Pre- and perinatal complications have been implicated in the onset and clinical expression of Tourette syndrome albeit with considerable inconsistencies across studies. Also, little is known about their role in co-occurring obsessive-compulsive disorder (OCD) and attention-deficit/hyperactivity disorder (ADHD) in individuals with a tic disorder. Therefore, we aimed to investigate the role of pre- and perinatal complications in relation to the presence and symptom severity of chronic tic disorder and co-occurring OCD and ADHD using data of 1113 participants from the Tourette International Collaborative Genetics study. This study included 586 participants with a chronic tic disorder and 527 unaffected family controls. We controlled for age and sex differences by creating propensity score matched subsamples for both case-control and within-case analyses. We found that premature birth (OR = 1.72) and morning sickness requiring medical attention (OR = 2.57) were associated with the presence of a chronic tic disorder. Also, the total number of pre- and perinatal complications was higher in those with a tic disorder (OR = 1.07). Furthermore, neonatal complications were related to the presence (OR = 1.46) and severity (b = 2.27) of co-occurring OCD and also to ADHD severity (b = 1.09). Delivery complications were only related to co-occurring OCD (OR = 1.49). We conclude that early exposure to adverse situations during pregnancy is related to the presence of chronic tic disorders. Exposure at a later stage, at birth or during the first weeks of life, appears to be associated with co-occurring OCD and ADHD.

The prevalence of diagnosed tourette syndrome in Canada: A national population-based study

OBJECTIVE

The objective of this study was to examine: (1) the prevalence of diagnosed Tourette syndrome in Canada by sex in youth (aged 12-17) and adults and (2) socioeconomic factors in this population.

BACKGROUND

The majority of epidemiological studies of tics have focused on children and youth, with few studies describing the prevalence of tics in adult populations.

METHODS

Canadian data on Tourette syndrome prevalence were derived from the Canadian Community Health Survey 2010 and 2011 cycles, a Statistics Canada population-based cross-sectional survey that collects information related to health status. We determined the prevalence of diagnosed Tourette syndrome and examined sociodemographic factors, including age, sex, education, income, employment, and birthplace.

RESULTS

Overall, 122,884 Canadians participated in the surveys, with 122 participants diagnosed with Tourette syndrome. The prevalence of Tourette syndrome was higher in males in youth: 6.03 per 1000 (95% confidence interval: 3.24-8.81) in males versus 0.48 per 1,000 (95% confidence interval: 0.05-0.91) in females, with a prevalence risk ratio of 5.31 (95% confidence interval: 2.38-11.81). In adults, the prevalence of Tourette syndrome was 0.89 per 1,000 (95% confidence interval: 0.48-1.29) in males versus 0.44 (95% confidence interval: 0.16.0-0.71) in females, with a prevalence risk ratio of 1.93 (95% confidence interval: 1.21-3.08). After adjusting for age and sex, adults with Tourette syndrome had lower odds of receiving postsecondary education or being employed and higher odds of having income lower than the median and receiving governmental support.

CONCLUSION

Data on the prevalence of Tourette syndrome in adults are scarce because most studies focus on children. Our data demonstrate a decreasing prevalence risk ratio for sex in adults compared to children. A diagnosis of Tourette syndrome is associated with lower education, income, and employment in adulthood. © 2016 International Parkinson and Movement Disorder Society.

Prenatal Maternal Smoking and Tourette Syndrome: A Nationwide Register Study

This is the first nationwide register-based study to examine the relationship between prenatal maternal smoking and Tourette syndrome. A total of 767 children diagnosed with Tourette syndrome were identified from the Finnish Hospital Discharge Register. Each case was matched to four controls. Information on maternal smoking during pregnancy was obtained from the Finnish Medical Birth Register. Conditional logistic regression models were used for statistical analyses. Prenatal maternal smoking was associated with Tourette syndrome when comorbid with ADHD (OR 4.0, 95 % CI 1.2-13.5, p = 0.027 for exposure during first trimester, OR 1.7, 95 % CI, 1.05-2.7, p = 0.031 for exposure for the whole pregnancy). There was no association between maternal smoking during pregnancy and Tourette syndrome without comorbid ADHD (OR 0.5, 95 % CI 0.2-1.3, p = 0.166, OR 0.9, 95 % CI 0.7-1.3, p = 0.567). Further research is needed to elucidate the mechanisms behind the association between prenatal maternal smoking and Tourette syndrome with comorbid ADHD.

Parental mood during pregnancy and post-natally is associated with offspring risk of Tourette syndrome or chronic tics: prospective data from the Avon Longitudinal Study of Parents and Children (ALSPAC)

Little is known about risk factors for Tourette syndrome (TS) and chronic tic disorders (CT) but maternal psychological morbidity in pregnancy may be associated with TS/CT. We examined whether pre- and post-natal parental anxiety and/or depression are associated with risk of TS/CT in the Avon Longitudinal Study of Parents and Children. We compared self-reported anxiety and depression measures collected prospectively at four time points (18 and 32 weeks prenatally, and 8 weeks and 8 months post-natally) among parents of children who subsequently met criteria for TS/CT at 13 years of age as compared to other children from the cohort. We adjusted for various socioeconomic measures and tested both for time period-specific exposure and chronic exposure using multivariable logistic regression models. 122 children had TS/CT (50 TS, 72 CT) and 5968 children had no tics. In crude analyses, both pre- and post-natal maternal anxiety and depression, but only post-natal paternal depression at 8 months, showed associations with TS/CT. In the final, adjusted multivariable models, chronic maternal anxiety (odds ratio 2.17, 95% CI 1.23, 3.84, p = 0.007) and pre-natal maternal depression (odds ratio 1.86, 95% CI 1.02, 3.39, p = 0.04) showed associations with TS/CT though the latter was consistent with chance (p = 0.07) after adjustment for past maternal depression. We find associations between maternal psychological morbidity pre- and post-natally and risk of future TS/CT in offspring. These associations may reflect either shared genetic susceptibility or a pre-natal exposure. Further work is required to see if these findings can be replicated in larger datasets.

The role of GRIN2B in Tourette syndrome: Results from a transmission disequilibrium study

BACKGROUND

Previous studies have indicated that dopamine interacts with glutamatergic projection neurons and that N-methyl-d-aspartate (NMDA) receptors might be involved in the pathogenesis of Tourette syndrome (TS). In this study, we examined whether two functional polymorphisms (rs1805476 and rs1805502) in the 3'UTR of the NMDA receptor 2B subunit gene (GRIN2B) were associated with TS in Chinese Han trios.

METHODS

DNA samples collected from 261 TS nuclear families were genotyped by PCR and direct sequencing technology. Haplotype relative risk (HRR), transmission disequilibrium test (TDT) and Haplotype-based haplotype relative risk (HHRR) analyses were performed on the genotype data.

RESULTS

We found an over-transmission of the A allele in rs1805476 and the T allele in rs1805502 from parents to their affected children, using the HRR (rs1805476: HRR=0.696, χ(2)=4.161, P=0.041, 95% CI: 0.491-0.986; rs1805502: HRR=0.697, χ(2)=3.954, P=0.047, 95% CI: 0.488-0.995). There was also strong evidence for a linkage between polymorphisms and TS using the TDT (rs1805476: TDT=5.447, df=1, P=0.024; rs1805502: TDT=5.233, df=1, P=0.027).

LIMITATIONS

The sample is small and the current population is just limited to the Chinese Han population.

CONCLUSIONS

These data support the hypothesis that GRIN2B might play a major role in the pathogenesis of TS in Chinese Han trios. However, these results need to be replicated using larger datasets collected from different populations.

Neurobehavioral aspects, pathophysiology, and management of Tourette syndrome

PURPOSE OF REVIEW

This update summarizes progress in understanding Tourette syndrome clinical characteristics, etiology, and treatment over the past year.

RECENT FINDINGS

Premonitory sensory phenomena were found to have important impacts on Tourette syndrome quality of life. A rare genetic form of Tourette syndrome due to L-histidine-decarboxylase mutation, with similar features in human and rodent, has inspired new research on functional anatomy of Tourette syndrome. In response to new data, treatment guidelines have been revised to include behavioral therapy as first-line treatment. Novel dopamine receptor antagonists aripiprazole and ecopipam have shown potential efficacy - as well as tolerability concerns. Recent work has suggested efficacy and tolerability of topiramate and fluphenazine, but more rigorous studies are needed to further understand their role in Tourette syndrome management. Recent consensus guidelines explain when deep brain stimulation can be considered for severe refractory cases under a multidisciplinary team.

SUMMARY

More research is needed to identify better tolerated treatments for, to understand pathophysiology or functional anatomy of, and to predict or influence longitudinal outcome of Tourette syndrome.

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.

Prenatal and Perinatal Morbidity in Children with Tic Disorders: A Mainstream School-based Population Study in Central Spain

Background

While current research suggests that genetic factors confer the greatest risk for the development of tic disorders, studies of environmental factors are relatively few, with a lack of consistent risk factors across studies. Our aim is to analyze the association of tic disorders with exposure to prenatal and perinatal morbidity.

Methods

This was a nested case–control study design. Cases and controls were selected and identified from a mainstream, school-based sample. The diagnosis of tic disorders was assigned by a movement disorder neurologist using ‘Diagnostic and statistical manual of mental disorders, 4th edition, text revision’ criteria, and neuropsychiatric comorbidities were screened using the Spanish computerized version of the Diagnostic Interview Schedule for Children Predictive Scale. Information regarding the exposure to pre-perinatal risk factors was collected by a retrospective review of the birth certificates. Logistic regression analyses were then performed to test the association of tic disorders with pre-perinatal risk factors.

Results

Out of 407 participants, complete pre-perinatal data were available in 153 children (64 with tics and 89 without tics). After adjusting for family history of tics, neonatal respiratory distress syndrome, body mass index, prenatal infection, and coexisting comorbid neuropsychiatric disturbances, tic disorders were associated with prenatal exposure to tobacco (odds ratio [OR] = 3.07, 95% confidence interval [CI] 1.24–7.60, p = 0.007), and cesarean section (OR = 5.78, 95% CI 1.60–20.91, p = 0.01).

Discussion

This nested case–control study of children with tic disorders demonstrates higher adjusted odds for tics in children with exposure to cesarean delivery and maternal smoking. Longitudinal, population-based samples are required to confirm these results.

Association between pre- and perinatal exposures and Tourette syndrome or chronic tic disorder in the ALSPAC cohort

BACKGROUND

Tourette syndrome and chronic tic disorder are heritable but aetiologically complex. Although environment plays a role in their development, existing studies of non-genetic risk factors are inconsistent.

AIMS

To examine the association between pre- and perinatal exposures and Tourette syndrome/chronic tic disorder in the Avon Longitudinal Study of Parents and Children (ALSPAC) prospective longitudinal pre-birth cohort.

METHOD

Relationships between exposures and Tourette syndrome/chronic tic disorder were examined in 6090 children using logistic regression.

RESULTS

Maternal alcohol and cannabis use, inadequate maternal weight gain and parity were associated with Tourette syndrome or Tourette syndrome/chronic tic disorder. Other previously reported exposures, including birth weight and prenatal maternal smoking, were not associated with Tourette syndrome/chronic tic disorder.

CONCLUSIONS

This study supports previously reported relationships between Tourette syndrome/chronic tic disorder and prenatal alcohol exposure, and identifies additional previously unexplored potential prenatal risk factors.