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)

Risk of Neurodevelopmental Disorders in Offspring of Parents with Major Depressive Disorder: A Birth Cohort Study

Studies have reported inconsistent results regarding associations between parental depression and offspring neurodevelopmental disorders, such as developmental delay and autism spectrum disorder (ASD). In all, 7,593 children who were born between 1996 and 2010 in Taiwan and had at least one parent with major depressive disorder and 75,930 birth-year- and sex-matched children of parents without major depressive disorder were followed from 1996 or time of birth to the end of 2011. Intergroup differences in neurodevelopmental conditions-including ASD, attention-deficit hyperactivity disorder (ADHD), tic disorder, developmental delay, and intellectual disability (ID)-were assessed. Compared with the children in the control group, the children of parents with major depression were more likely [hazard ratio (HR), 95% confidence interval (CI)] to develop ADHD (1.98, 1.80-2.18), ASD (1.52, 1.16-1.94), tic disorder (1.40, 1.08-1.81), developmental delay (1.32, 1.20-1.45), and ID (1.26, 1.02-1.55). Parental depression was associated with offspring neurodevelopmental disorders, specifically ASD, ADHD, developmental delay, ID, and tic disorder. Therefore, clinicians should closely monitor the neurodevelopmental conditions of children of parents with depression.

A review of common influencing factors and possible mechanisms associated with allergic diseases complicating tic disorders in children

Over the past few decades, the incidence of childhood allergic diseases has increased globally, and their impact on the affected child extends beyond the allergy itself. There is evidence of an association between childhood allergic diseases and the development of neurological disorders. Several studies have shown a correlation between allergic diseases and tic disorders (TD), and allergic diseases may be an important risk factor for TD. Possible factors influencing the development of these disorders include neurotransmitter imbalance, maternal anxiety or depression, gut microbial disorders, sleep disturbances, maternal allergic status, exposure to tobacco, and environmental factors. Moreover, gut microbial disturbances, altered immunological profiles, and DNA methylation in patients with allergic diseases may be potential mechanisms contributing to the development of TD. An in-depth investigation of the relationship between allergic diseases and TD in children will be important for preventing and treating TD.

Paternal health in the first 12-13 years of the ALSPAC study

The Avon Longitudinal Study of Parents and Children (ALSPAC) collected information from the enrolled pregnancy onwards to identify features of the environment in which the study child was brought up. Among data collected were features concerning the health of the mothers' partners - generally the study father. This was an important feature since the father's physical and mental health can have a long-term effect on the family. In this Data Note we describe the data available on the father's health from pregnancy until 12 years after the offspring was born. Not only is this a valuable addition to the environmental information available for studies of the child's development and the mental health of the mother over time, but it will provide a useful description of the father himself during adulthood.

Direct additive genetics and maternal effect contribute to the risk of Tourette disorder

BACKGROUND

Risk for Tourette disorder, and chronic motor or vocal tic disorders (referenced here inclusively as CTD), arise from a combination of genetic and environmental factors. While multiple studies have demonstrated the importance of direct additive genetic variation for CTD risk, little is known about the role of cross-generational transmission of genetic risk, such as maternal effect, which is not transmitted via the inherited parental genomes. Here, we partition sources of variation on CTD risk into direct additive genetic effect (narrow-sense heritability) and maternal effect.

METHODS

The study population consists of 2 522 677 individuals from the Swedish Medical Birth Register, who were born in Sweden between 1 January 1973 and 31 December 2000, and followed for a diagnosis of CTD through 31 December, 2013. We used generalised linear mixed models to partition the liability of CTD into: direct additive genetic effect, genetic maternal effect and environmental maternal effect.

RESULTS

We identified 6227 (0.2%) individuals in the birth cohort with a CTD diagnosis. A study of half-siblings showed that maternal half-siblings had twice higher risk of developing a CTD compared with paternal ones. We estimated 60.7% direct additive genetic effect (95% credible interval, 58.5% to 62.4%), 4.8% genetic maternal effect (95% credible interval, 4.4% to 5.1%) and 0.5% environmental maternal effect (95% credible interval, 0.2% to 7%).

CONCLUSIONS

Our results demonstrate genetic maternal effect contributes to the risk of CTD. Failure to account for maternal effect results in an incomplete understanding of the genetic risk architecture of CTD, as the risk for CTD is impacted by maternal effect which is above and beyond the risk from transmitted genetic effect.

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.

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.

Depressive symptoms measured using the Edinburgh Postnatal Depression Scale in mothers and partners in the ALSPAC Study: A data note

Depression is a leading cause of disability and is associated with a number of adverse offspring outcomes when it occurs in parents. Depression is present in men and women at different rates, and recent research suggests that symptom profiles between the sexes may differ. Longitudinal data are needed to answer remaining questions about the long-term course, gender differences, antecedents and outcomes of depression. The Avon Longitudinal Study of Parents and Children (ALSPAC) is a large birth cohort study in England which administered one of the most commonly used depression instruments, the Edinburgh Postnatal Depression Scale (EPDS) at 11 timepoints in mothers and at 10 timepoints in their partners. In addition to repeated measurements of the EPDS, ALSPAC has a wealth of participant data on biological, social, demographic, and lifestyle factors. The purpose of this data note is to introduce potential users of the data to the characteristics of the EPDS in ALSPAC, as well as some key considerations when using the data.

Rhynchophyllin attenuates neuroinflammation in Tourette syndrome rats via JAK2/STAT3 and NF-κB pathways

The aim of this study was designed to investigate the effects of rhynchophyllin (RH) on neuroinflammation in Tourette syndrome (TS) rats. TS model was established in rats by the injection of selective 5-HT2A/2C agonist 1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). Behavior in DOI-induced rats was tested. Inflammatory cytokines levels such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in serum and striatum were detected. The expression levels of janus kinase 2 (JAK2)/signal transducer and transcription activator 3 (STAT3) and nuclear factor (NF)-κB pathways in striatum were measured by Western blot. Data indicated that RH can significantly reduce the numbers of nodding experiment of TS rats. RH significantly decreased IL-6, IL-1β, and TNF-α in serum and striatum of TS rats, with altered expression of P-JAK2, P-STAT3, P-NF-κBp65, and P-IκBα in TS rats, as evidenced by Western blot analysis and immunohistochemistry, suggesting that the regulation of JAK2/STAT3 and NF-κB pathways might be involved in the mechanism of RH on TS.

The effects of comorbid Tourette symptoms on distress caused by compulsive-like behavior in very young children: a cross-sectional study

BACKGROUND

Many children 4 to 6 years old exhibit compulsive-like behavior, often with comorbid Tourette symptoms, making this age group critical for investigating the effects of having comorbid Tourette symptoms with compulsive-like behavior. However, these effects have not yet been elucidated: it is unclear whether having comorbid tics with compulsive-like behavior leads to lower quality of life. This cross-sectional study aims to investigate the effect of comorbid Tourette symptoms on distress caused by compulsive-like behavior in very young children.

METHODS

Self-administered questionnaires were distributed to guardians of children aged 4 to 6 attending any of the 59 public preschools in a certain ward in Tokyo, Japan. The questionnaire contained questions on the presence of Tourette symptoms, the presence of specific motor and vocal tics, frequency/intensity of compulsive-like behavior, and the distress caused by compulsive-like behavior, which was rated on a scale of 1 to 5. Additionally, questions on autism spectrum disorder (ASD) traits, attention-deficit/hyperactivity disorder (ADHD) traits, internalizing behavior traits, and externalizing behavior traits were included in the questionnaire as possible confounders of distress caused by compulsive-like behavior. Wilcoxon rank-sum tests were conducted to compare the distress caused by compulsive-like behavior and frequency/intensity of compulsive-like behavior between children in the Tourette symptoms group and the non-Tourette symptoms group. Furthermore, a stepwise regression analysis was performed to assess the effects of the independent variables on distress caused by compulsive-like behavior. Another stepwise regression analysis was performed to assess the relationship between distress caused by compulsive-like behavior and the presence of five specific motor and vocal tics.

RESULTS

Of the 675 eligible participants, distress due to compulsive-like behavior was significantly higher in children in the Tourette symptoms group compared to the non-Tourette symptoms group (2.00 vs 1.00, P < 0.001). Stepwise regression analysis showed that frequency/intensity of compulsive-like behavior, being in the Tourette symptoms group, ASD traits, and internalizing behavior traits were predictors of distress due to compulsive-like behavior. Two specific tics, repetitive noises and sounds and repetitive neck, shoulder, or trunk movements, were significant predictors of distress due to compulsive-like behavior.

CONCLUSIONS

Comorbid Tourette symptoms may worsen distress caused by compulsive-like behavior in children 4 to 6 years old, and specific motor and vocal tics may lead to greater distress.

Rhynchophylline Attenuates Tourette Syndrome via BDNF/NF-κB Pathway In Vivo and In Vitro

Tourette syndrome (TS) is characterized by one of the chronic neuropsychiatric disorders in multiple children, and the pathogenesis of Tourette syndrome (TS) has not been previously elucidated.The aim of this study was designed to investigate the effects of rhynchophylline (RH) on Tourette syndrome (TS) in rats.TS model was established in rats and BV2 cells by the selective 5-HT2A/2C agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI). Behavior evaluations including stereotypy recording and autonomic activity test were performed. Inflammatory cytokine levels such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in serum, striatum, and cell supernatant were detected. The expression levels of BDNF/NF-κB pathway in striatum and BV2 cells were measured by Western blot. Dopamine (DA) and dopamine receptor D 2 (D2) in striatum were also measured.Data indicated that RH significantly decreased IL-6, IL-1β, and TNF-α in serum, striatum, and cell supernatant of TS model, with altered expression of P-NF-κBp65, P-IκBα, and BDNF in TS rats, and DOI-induced BV2 cells, as evidenced by Western blot analysis and immunohistochemistry analysis. RH also significantly reduced the levels of DA and D2 in striatum.Our results shown that the regulation of BDNF/NF-κB pathway might be involved in the effects of RH on TS model.

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;

Parental Psychopathology and Tourette Syndrome/Chronic Tic Disorder in Offspring: A Nationwide Case-Control Study

OBJECTIVE

To determine the associations between maternal and paternal psychiatric diagnoses and Tourette syndrome (TS)/chronic tic disorder (CT) in a nationwide study.

METHOD

This nested case-control study linked data derived from three national registers. All singletons born and diagnosed with TS/CT in Finland between January 1991 and December 2010 were identified (n = 1,120) and matched to four controls (n = 4,299). Conditional logistic regression was used to examine the associations between parental psychopathology and TS/CT.

RESULTS

Altogether, 24.9% of patients with TS/CT and 12.0% of controls had a mother with a psychiatric diagnosis. Similarly, 17.9% and 12.9% had a father with a psychiatric diagnosis. Any maternal and any paternal psychiatric diagnosis was associated with offspring TS/CT (odds ratio [OR] 2.3; 95% CI 1.9-2.7 and OR 1.2; 95% CI 1.01-1.5, respectively). The association between maternal psychiatric diagnosis and TS/CT was stronger than that between paternal psychiatric diagnosis and TS/CT (p < .001). Maternal personality disorders (OR 3.1, 95% CI 1.9-5.1), anxiety disorders (OR 2.6, 95% CI 1.9-3.5), affective disorders (OR 2.3, 95% CI 1.8-2.9), psychotic disorders (OR 2.0, 95% CI 1.2-3.3), and addiction disorders (OR 1.8, 95% CI 1.1-2.8) were associated with TS/CT. Paternal OCD (OR 6.5, 95% CI 1.1-39.5) and anxiety disorders (OR 1.5, 95% CI 1.1-2.3) were associated with TS/CT.

CONCLUSION

Parental psychiatric diagnoses (especially in the mother) are associated with diagnosed offspring TS/CT. Further studies are required before the results can be generalized to all children with TS/CT. The associations between maternal psychiatric disorders and TS may reflect both maternal specific environmental and/or genetic influences.

Prenatal Maternal Smoking and Increased Risk for Tourette Syndrome and Chronic Tic Disorders

OBJECTIVE

We assessed the role of prenatal maternal smoking in risk for Tourette syndrome and chronic tic disorder (TS/CT) and pediatric-onset obsessive-compulsive disorder (OCD).

METHOD

In an analysis of 73,073 singleton pregnancies from the Danish National Birth Cohort, we calculated incidence rates (IR) per 1,000 person-year for TS/CT and OCD. We then determined crude and adjusted hazard ratios and 95% CIs associated with prenatal maternal smoking, considering smoking as a dichotomous (yes/no) variable or a stratified variable (no smoking, light smoking, and heavy smoking [≥10 cigarettes/day]). Additional analyses examined the effect of maternal smoking on risk for TS/CT with other comorbid psychiatric conditions.

RESULTS

In final adjusted analyses, heavy smoking was associated with a 66% increased risk for TS/CT (adjusted hazard ratio = 1.66, 95% CI = 1.17-2.35). In addition, heavy smoking was associated with a 2-fold increased risk for TS/CT with comorbid attention-deficit/hyperactivity disorder (ADHD), and both light and heavy smoking were associated with a more than 2-fold increased risk for TS/CT with any non-ADHD psychiatric comorbidity. Our parallel analyses of pediatric-onset OCD were likely underpowered but showed similar relationships.

CONCLUSION

Prenatal maternal smoking was associated with increased risk for TS/CT as well as TS/CT with comorbid psychiatric conditions, even after adjustment for several important variables, including maternal psychiatric history, socioeconomic status, and partner smoking. Our findings point to a pathway linking prenatal tobacco exposure and altered brain development to TS/CT.

Tourette syndrome research highlights 2015

We present selected highlights from research that appeared during 2015 on Tourette syndrome and other tic disorders. Topics include phenomenology, comorbidities, developmental course, genetics, animal models, neuroimaging, electrophysiology, pharmacology, and treatment. We briefly summarize articles whose results we believe may lead to new treatments, additional research or modifications in current models of TS.

The First World Congress on Tourette Syndrome and Tic Disorders: Controversies and Hot Topics in Etiology and Treatment

The first World Congress on Tourette Syndrome and Tic Disorders was held in London, June 2016 by the Tourette Association of America, Tourettes Action (UK), and the European Society for the Study of Tourette Syndrome. Presentations arising from large-scale collaborative projects were an important component of the scientific programme. This article focuses on areas raised in the hot topics session and two moderated debates, which covered emerging research in etiology and treatment. The hot topics ranged across genetics, arguably including the first confirmed Tourette Syndrome (TS) susceptibility gene NRXN1, neurocognition, and neurophysiology, including the possibility of a neurocognitive endophenotype for TS and the use of depth and cortical surface electrodes to investigate the neurophysiology of tics on the background of the evolving field of deep brain stimulation (DBS), to novel treatment approaches such as dental orthotics and an online behavioral intervention. The debates aired controversies in treatment; pharmacotherapy vs. behavioral treatment and the place of medical cannabinoids. These sessions demonstrate the vibrancy of a field that has considerably expanded in the last decade, the significant progress that has been made, and the direction that some of the most fruitful next phases of research will take.