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

Pregnancy complications and childhood mental health: is the association modified by sex or adverse social circumstances? Findings from the 'growing up in Ireland' national infant cohort study

Specific pregnancy complications, socioeconomic position and sex have all been independently associated with child mental health outcomes, but their combined effects remain unclear. We examined whether total number of complications experienced in the pregnancy associated with mental health at 5 and 9-years, and whether this varied by sex or adverse social circumstances. Pregnancy complications were self-reported at 9-months post-natally from a list of 16 complications. Parents completed the Strengths and Difficulties Questionnaire (SDQ) when their child was 5 and 9-years. The primary outcome was the SDQ-total and scoring in the clinical range (> 16) was a secondary outcome. We applied generalized linear mixed models to a large nationally representative Irish cohort (GUI; n = 11,134). Analyses were adjusted for sex, adverse social circumstances (at 9-months), and gestational smoking. We included an interaction term between pregnancy complications and each variable respectively in separate models to examine if associations varied by sex or adverse circumstances.After controlling for covariates, total complications associated with mental health at 5 and 9-years. Each additional pregnancy complication conferred a 10% higher total-SDQ score (exponentiated co-efficient 1.10 [95%CI 1.06-1.14], 1.20 [1.15-1.26], 1.20 [1.12-1.29] and 1.34 [1.21-1.48] for 1, 2, 3 and 4 + complications respectively). For the dichotomised outcome, generally increasing odds for clinical levels of mental health difficulties were observed (OR 1complication = 1.89, 95%CI [1.37-2.59]; OR 2complications = 2.31, 95%CI [1.53-3.50]; OR 3complications = 1.77, 95%CI [0.89-3.52]; OR 4 + complications = 6.88, 95%CI [3.29-14.40]). Females had significantly lower odds of exhibiting clinically significant mental health difficulties than males (OR = 0.43, 95%CI[0.32-0.57]).There was no evidence that the association between pregnancy complications and child's mental health varied by sex or social circumstances at 5 or 9-years. Males exposed to numerous pregnancy complications in the context of adverse social circumstances had the highest predicted probability of having mental health difficulties in middle childhood.

Beyond TORCH: A narrative review of the impact of antenatal and perinatal infections on the risk of disability

Infections and inflammation during pregnancy or early life can alter child neurodevelopment and increase the risk for structural brain abnormalities and mental health disorders. There is strong evidence that TORCH infections (i.e., Treponema pallidum, Toxoplasma gondii, rubella virus, cytomegalovirus, herpes virus) alter fetal neurodevelopment across multiple developmental domains and contribute to motor and cognitive disabilities. However, the impact of a broader range of viral and bacterial infections on fetal development and disability is less well understood. We performed a literature review of human studies to identify gaps in the link between maternal infections, inflammation, and several neurodevelopmental domains. We found strong and moderate evidence respectively for a higher risk of motor and cognitive delays and disabilities in offspring exposed to a range of non-TORCH pathogens during fetal life. In contrast, there is little evidence for an increased risk of language and sensory disabilities. While guidelines for TORCH infection prevention during pregnancy are common, further consideration for prevention of non-TORCH infections during pregnancy for fetal neuroprotection may be warranted.

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.

Association of Pre- and Perinatal Risk Factors With Tourette Syndrome or Chronic Tic Disorders in a Korean School-Age Population

Objectives

Tic disorders are highly heritable; however, growing evidence suggests that environmental factors play a significant role in their pathogenesis. Studies on these factors have been inconsistent, with conflicting results. Therefore, this study aimed to examine the associations of pre- and perinatal exposure to Tourette syndrome (TS) or chronic tic disorders (CTD) in Korean school-aged children.

Methods

This case-control study used data from a large prospective cohort study. The primary outcome was TS/CTD diagnosis according to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) criteria and Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version-Korean Version. Demographic, pre-, and perinatal information was obtained from the maternal questionnaires. Data between the TS/CTD and control groups were compared using the chi-squared or Student's t-test, as appropriate. Two-step logistic regression analyses were used to test the association between TS/CTD and pre- and perinatal risk factors.

Results

We included of 223 children (78 with TS/CTD and 145 controls). Significant differences in the demographic data between the two groups were observed. The male sex ratio, mean parental age, parental final education level, and family history of tics were included as confounders. In the final adjusted multivariable model, TS/CTD was significantly associated with antiemetic exposure during pregnancy (odds ratio [OR]=16.61, 95% confidence interval [CI] 1.49-185.22, p=0.02) and medically assisted reproduction (OR=7.89, 95% CI 2.28-27.28, p=0.01).

Conclusion

Antiemetic exposure and medically assisted reproduction are significantly associated with the risk of TS/CTD. These results should be replicated in future prospective and gene-by-environment studies.

Co-Occurrence of Tic Disorders and Attention-Deficit/Hyperactivity Disorder-Does It Reflect a Common Neurobiological Background?

BACKGROUND

The co-existence of tic disorders and attention-deficit/hyperactivity disorder (TD + ADHD) has proven to be highly important in daily clinical practice. The factor ADHD is not only associated with further comorbidities, but also has a long-term negative psychosocial effect, while the factor TD is usually less disturbing for the major part of the patients. It remains unclear how far this is related to a different neurobiological background of the associated disorders or whether TD + ADHD reflects a common one.

OBJECTIVE

This review provides an update on the neurobiological background of TD + ADHD in order to better understand and treat this clinical problem, while clarifying whether an additive model of TD + ADHD holds true and should be used as a basis for further clinical recommendations.

METHOD

A comprehensive research of the literature was conducted and analyzed, including existing clinical guidelines for both TD and ADHD. Besides genetical and environmental risk factors, brain structure and functions, neurophysiological processes and neurotransmitter systems were reviewed.

RESULTS

Only a limited number of empirical studies on the neurobiological background of TD and ADHD have taken the peculiarity of co-existing TD + ADHD into consideration, and even less studies have used a 2 × 2 factorial design in order to disentangle the impact/effects of the factors of TD versus those of ADHD. Nevertheless, the assumption that TD + ADHD can best be seen as an additive model at all levels of investigation was strengthened, although some overlap of more general, disorder non-specific aspects seem to exist.

CONCLUSION

Beyond stress-related transdiagnostic aspects, separate specific disturbances in certain neuronal circuits may lead to disorder-related symptoms inducing TD + ADHD in an additive way. Hence, within a classificatory categorical framework, the dimensional aspects of multilevel diagnostic-profiling seem to be a helpful precondition for personalized decisions on counselling and disorder-specific treatment in TD + ADHD.

Family, personal, parental correlates and behavior disturbances in school-aged boys with attention-deficit/hyperactivity disorder (ADHD): a cross-sectional study

BACKGROUND

To evaluate the relationship among family, personal, parental correlates, and behavioral disturbances in boys with attention-deficit/hyperactivity disorder (ADHD).

METHODS

We performed a hospital-based cross-sectional study. School-aged boys who first visited the hospital between 2000 and 2011 with ADHD were identified. Through medical records review, demographic information, family characteristics, personal characteristics, parental characteristics, and the Child Behavior Checklist (CBCL) collected during the first outpatient visit were retrieved. A T-score higher than 63 in the internalizing or externalizing subscale of the CBCL indicated severe behavioral disturbances in each domain. Multivariable logistic regression was used to evaluate the relationship between the correlates and behavioral disturbances. Eligible patients were further classified into groups without behavioral disturbance, with either only severe internalizing or only severe externalizing behaviors, or with both behaviors. Multivariable ordinal logistic regression was used to investigate the association between the correlates and the number of types of behavioral disturbances.

RESULTS

A total of 1855 boys with ADHD were included. In the multivariable logistic regression, family factors, including being first-born, living in a family not with both parents, and family history of mental disorder, were associated with severe internalizing and externalizing behaviors. Personal factors, including prenatal complications, perinatal complications, and medical and psychiatric comorbidities, were associated with severe internalizing behaviors, but only prenatal complications and medical comorbidities were associated with severe externalizing behaviors. Parental factors were only associated with severe externalizing behaviors. A higher paternal education level had a protective effect, but younger motherhood increased the risk. In ordinal logistic regression, these factors were also associated with more types of behavioral disturbances.

CONCLUSIONS

Multiple factors are related to behavioral disturbances in ADHD. Our study reported the association among family, personal, parental factors, severe internalizing behavior, severe externalizing behavior, and number of behavioral disturbances in boys with ADHD. However, the impacts differed as the behavior phenotypes varied. Further research is needed to better understand the heterogeneity of ADHD behavior.

Through the prism of comorbidity: A strategic rethinking of early intervention in obsessive-compulsive disorder

The diagnostic criteria for obsessive-compulsive disorder (OCD) have undergone minor changes in DSM-5 yet a major turnaround intervened in the overarching categorical allocation. OCD indeed has been separated from the anxiety disorders and included in an autonomous class of OCD-related disorders. Converging factors, i.e., the specificity of the clinical phenotype, the robust evidence for familial aggregation, the availability of effective treatments, and the increasing awareness of the role of environmental factors in its onset and course make OCD a suited target for tailored early intervention programs. However, studies on the topic are still scarce and OCD remains marginally conceptualized within an overdue early detection/intervention framework. Starting from the consolidated clinical evidence of OCD extensive comorbidity with schizophrenia-spectrum and bipolar disorders, we articulate a strategic proposal for a more integral incorporation of OCD within early detection and intervention paradigm.

Tourettic OCD: Current understanding and treatment challenges of a unique endophenotype

Obsessive compulsive disorder (OCD) and chronic tic disorders (CTD) including Tourette Syndrome (TS) are often comorbid conditions. While some patients present with distinct symptoms of CTD and/or OCD, a subset of patients demonstrate a unique overlap of symptoms, known as Tourettic OCD (TOCD), in which tics, compulsions, and their preceding premonitory urges are overlapping and tightly intertwined. The specific behaviors seen in TOCD are typically complex tic-like behaviors although with a compulsive and partially anxious nature reminiscent of OCD. TOCD is not classified within the Diagnostic and Statistical Manual of Mental Disorders fifth edition (DSM-5) as an independent diagnostic entity, but mounting evidence suggests that TOCD is an intermediate neuropsychiatric disorder distinct from either TS or OCD alone and as such represents a unique phenomenology. In this review of TOCD we discuss clinical, genetic, environmental, neurodevelopmental, and neurocircuit-based research to better characterize our current understanding of this disorder. TOCD is characterized by earlier age of onset, male predominance, and specific symptom clusters such as lower tendency toward compulsions related to checking, cleaning, and reassurance seeking and higher tendency toward compulsions such as rubbing, tapping, or touching associated with symmetry concerns or thoughts of exactness. Functional magnetic resonance imaging (fMRI) imaging suggests that TOCD symptoms may arise from involvement of an intermediate neurocircuitry distinct from classic OCD or classic CTD. Small cumulative contributions from multiple genetic loci have been implicated, as have environmental factors such as infection and perinatal trauma. In addition, this review addresses the treatment of TOCD which is especially complex and often treatment resistant and requires pharmacology and behavioral therapy in multiple modalities. Given the distressing impact of TOCD on patients' functioning, the goal of this review is to raise awareness of this distinct entity toward the goal of improving standards of care.

Investigation of gene-environment interactions in relation to tic severity

Tourette syndrome (TS) is a neuropsychiatric disorder with involvement of genetic and environmental factors. We investigated genetic loci previously implicated in Tourette syndrome and associated disorders in interaction with pre- and perinatal adversity in relation to tic severity using a case-only (N = 518) design. We assessed 98 single-nucleotide polymorphisms (SNPs) selected from (I) top SNPs from genome-wide association studies (GWASs) of TS; (II) top SNPs from GWASs of obsessive-compulsive disorder (OCD), attention-deficit/hyperactivity disorder (ADHD), and autism spectrum disorder (ASD); (III) SNPs previously implicated in candidate-gene studies of TS; (IV) SNPs previously implicated in OCD or ASD; and (V) tagging SNPs in neurotransmitter-related candidate genes. Linear regression models were used to examine the main effects of the SNPs on tic severity, and the interaction effect of these SNPs with a cumulative pre- and perinatal adversity score. Replication was sought for SNPs that met the threshold of significance (after correcting for multiple testing) in a replication sample (N = 678). One SNP (rs7123010), previously implicated in a TS meta-analysis, was significantly related to higher tic severity. We found a gene-environment interaction for rs6539267, another top TS GWAS SNP. These findings were not independently replicated. Our study highlights the future potential of TS GWAS top hits in gene-environment studies.

Developmental Considerations in Obsessive Compulsive Disorder: Comparing Pediatric and Adult-Onset Cases

There appear to be two peaks of incidence of Obsessive Compulsive Disorder (OCD), one with a pre-adolescent onset and another in early adulthood. As new cases are added, the cumulative prevalence of OCD increases, but the great majority of cases have an onset in youth. The notion that early onset OCD represents a unique developmental subtype of the disorder has been considered by many researchers based on several specific age-related factors. Ascertainment and early intervention in affected youth is critical to abbreviate the functional impairments associated with untreated illness. In this paper we review the clinical, familial and translational biomarker correlates seen in early onset OCD that support the notion of a developmental subtype and discuss implications for research and treatment aimed at this cohort. The importance of cognitive, academic and social development tasks of childhood and adolescence, illness-specific and familial factors, and immune-mediated inflammatory factors are discussed, with their implications for management.

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.

Refractory Gilles de la Tourette Syndrome-Many Pieces That Define the Puzzle

Gilles de la Tourette syndrome (GTS) is a childhood onset neuropsychiatric disorder characterized by the presence of motor and vocal tics. The clinical spectrum of GTS is heterogeneous and varies from mild cases that do not require any medical attention to cases that are refractory to standard treatments. One of the unresolved issues is the definition of what constitutes treatment-refractory GTS. While for some other neuropsychiatric disorders, such as obsessive-compulsive disorder (OCD), a clear definition has been established, there is still no consensus with regard to GTS. One important issue is that many individuals with GTS also meet criteria for one or more other neurodevelopmental and neuropsychiatric disorders. In many individuals, the severity of these comorbid conditions contributes to the degree to which GTS is treatment refractory. The scope of this paper is to present the current state-of-the-art regarding refractory GTS and indicate possible approaches to define it. In closing, we discuss promising approaches to the treatment of individuals with refractory GTS.

The cognitive neuropsychiatry of Tourette syndrome

Introduction: Converging evidence from both clinical and experimental studies has shown that Tourette syndrome (TS) is not a unitary condition, but a cluster of multiple phenotypes, which encompass both tics and specific behavioural and cognitive symptoms (mainly attention-deficit and hyperactivity disorder and obsessive-compulsive disorder). Methods: We conducted a narrative review of the recent literature on the cognitive neuropsychiatry of TS. Results: Although clinical research has shown that TS is not associated with cognitive deficits per se, the findings of recent studies have suggested the presence of subtle alterations in specific cognitive functions. A promising line of research on imitative behaviour could provide a common background for the alterations in executive control and social cognition observed in TS. Two different (but not mutually exclusive) neurocognitive theories have recently suggested that TS could originate from altered perception-action binding and social decision-making dysfunction, respectively. Conclusions: Since the presence of behavioural comorbidities influences individualised treatment approaches, it is likely that a more precise characterisation of TS phenotypes, including cognitive aspects, will result in improved levels of care for patients with tic disorders.

Gastrodin attenuates neuroinflammation in DOI-induce Tourette syndrome in rats

OBJECTIVE

Tourette syndrome (TS) is a chronic neuropsychiatric disorder. Its clinical manifestations are involuntary and recurrent muscle twitch, resulting in motor twitch and occurrence twitch. Traditional Chinese medicine has obvious advantages in treating TS. The aim of this study was to investigate the effects and mechanism of gastrodin on 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI)-induced TS in rats.

METHODS

TS model was induced by DOI. Behaviors in TS rats were detected. The striatum, serum inflammatory factors interleukin-6, interleukin-1β, and tumor necrosis factor-a were detected by enzyme-linked immunosorbent assay. Western blot technique was used to detect the expressions of TLR/NF-κB and TLR/MAPK signaling pathways in the striatum.

RESULTS

Gastrodin can significantly improve behavioral changes of TS rats induced by DOI, reduce inflammatory factors in serum and striatum in TS rats, and inhibit activation of TLR/NF-κB and TLR/MAPK signaling in striatum in TS rats.

CONCLUSION

Gastrodin can significantly relieve the TS induced by DOI in rats. Its mechanism is related to the inhibition of striatal TLR/NF-κB and TLR/MAPK signaling activation.

European Multicentre Tics in Children Studies (EMTICS): protocol for two cohort studies to assess risk factors for tic onset and exacerbation in children and adolescents

Genetic predisposition, autoimmunity and environmental factors [e.g. pre- and perinatal difficulties, Group A Streptococcal (GAS) and other infections, stress-inducing events] might interact to create a neurobiological vulnerability to the development of tics and associated behaviours. However, the existing evidence for this relies primarily on small prospective or larger retrospective population-based studies, and is therefore still inconclusive. This article describes the design and methodology of the EMTICS study, a longitudinal observational European multicentre study involving 16 clinical centres, with the following objectives: (1) to investigate the association of environmental factors (GAS exposure and psychosocial stress, primarily) with the onset and course of tics and/or obsessive-compulsive symptoms through the prospective observation of at-risk individuals (ONSET cohort: 260 children aged 3-10 years who are tic-free at study entry and have a first-degree relative with a chronic tic disorder) and affected individuals (COURSE cohort: 715 youth aged 3-16 years with a tic disorder); (2) to characterise the immune response to microbial antigens and the host's immune response regulation in association with onset and exacerbations of tics; (3) to increase knowledge of the human gene pathways influencing the pathogenesis of tic disorders; and (4) to develop prediction models for the risk of onset and exacerbations of tic disorders. The EMTICS study is, to our knowledge, the largest prospective cohort assessment of the contribution of different genetic and environmental factors to the risk of developing tics in putatively predisposed individuals and to the risk of exacerbating tics in young individuals with chronic tic disorders.

Genetic Studies of Tic Disorders and Tourette Syndrome

Tourette syndrome (TS) is a complex disorder characterized by repetitive, sudden, and involuntary movements or vocalizations, called tics. Tics usually appear in childhood, and their severity varies over time. In addition to frequent tics, people with TS are at risk for associated problems including attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety, depression, and problems with sleep. TS occurs in most populations and ethnic groups worldwide, and it is more common in males than in females. Previous family and twin studies have shown that the majority of cases of TS are inherited. TS was previously thought to have an autosomal dominant pattern of inheritance. However, several decades of research have shown that this is unlikely the case. Instead, TS most likely results from a variety of genetic and environmental factors, not changes in a single gene. In the past decade, there has been a rapid development of innovative genetic technologies and methodologies, as well as significant progress in genetic studies of psychiatric disorders. In this review, we will briefly summarize previous genetic epidemiological studies of TS and related disorders. We will also review previous genetic studies based on genome-wide linkage analyses and candidate gene association studies to comment on problems of previous methodological and strategic issues. Our main purpose for this review will be to summarize the new genetic discoveries of TS based on novel genetic methods and strategies, such as genome-wide association studies (GWASs), whole exome sequencing (WES), and whole genome sequencing (WGS). We will also compare the new genetic discoveries of TS with other major psychiatric disorders in order to understand the current status of TS genetics and its relationship with other psychiatric disorders.

Systematic review of co-occurring OCD and TD: Evidence for a tic-related OCD subtype?

OBJECTIVE

The aim of this review is to summarize the current knowledge of associated features of co-occurring obsessive-compulsive disorder (OCD) and tic disorders (TD) and to critically evaluate hypotheses regarding the nature of their comorbidity.

METHOD

We conducted a systematic review following PRISMA guidelines. To this aim, the PubMed, PsychInfo and ISI Web of Knowledge databases were searched up to August 30, 2018. For gender and age-of-onset we additionally conducted meta-analyses.

RESULTS

One hundred eighty-nine studies met inclusion criteria. We substantiate some acknowledged features and report evidence for differential biological mechanisms and treatment response. In general, studies were of limited methodological quality.

CONCLUSIONS

Several specific features are reliable associated with co-occurring OCD + TD. The field lacks methodological sound studies. The review found evidence against and in favor for different hypotheses regarding the nature of comorbidity of OCD and TD. This could indicate the existence of a stepwise model of co-morbidity, or could be an artefact of the low methodological quality of studies.

Disentangling Tourette syndrome heterogeneity through hierarchical ascendant clustering

AIM

To explore the heterogeneity of Tourette syndrome as part of a neurodevelopmental spectrum.

METHOD

Using hierarchical ascendant clustering based on tic symptoms, developmental milestones, and neurodevelopmental comorbidities, we analyzed the heterogeneity of Tourette syndrome phenotypes in a sample of 174 children and adolescents with Tourette syndrome referred to a tertiary university clinic.

RESULTS

The model yielded three distinct clusters characterized as follows. In cluster 1, we found many neurodevelopmental comorbidities (including intellectual disabilities, autism spectrum disorder, attention-deficit-hyperactivity disorder [ADHD], and learning disabilities) and academic impairments. In cluster 2, patients had no other neurodevelopmental comorbidities. In cluster 3, patients had higher intelligence, a high frequency of attentional impairment, school problems related to both ADHD and unspecific attention difficulties, and handwriting problems related to the tics themselves. Interestingly, clusters did not differ in terms of family history or anxious-depressive comorbidities. The only other differences that emerged were related to prenatal or perinatal risk factors (more represented in cluster 1) and treatment profiles (higher rates of stimulants in cluster 1).

INTERPRETATION

We conclude that from a phenotypical perspective, Tourette syndrome is a heterogeneous syndrome with at least three main clusters that may help in addressing the etiological basis of Tourette syndrome and specific rehabilitative and therapeutic approaches.

WHAT THIS PAPER ADDS

The clustering of Tourette syndrome based on comorbidity with other neurodevelopmental conditions reveals three clusters. A group of patients with Tourette syndrome show school difficulties related to non-specific attention and writing problems. Analysing only children and adolescents helps to distinguish between developmental comorbid conditions and coexistent disorders.

Perinatal risk factors in Tourette's and chronic tic disorders: a total population sibling comparison study

Adverse perinatal events may increase the risk of Tourette's and chronic tic disorders (TD/CTD), but previous studies have been unable to control for unmeasured environmental and genetic confounding. We aimed to prospectively investigate potential perinatal risk factors for TD/CTD, taking unmeasured factors shared between full siblings into account. A population-based birth cohort, consisting of all singletons born in Sweden in 1973-2003, was followed until December 2013. A total of 3 026 861 individuals were identified, 5597 of which had a registered TD/CTD diagnosis. We then studied differentially exposed full siblings from 947 942 families; of these, 3563 families included siblings that were discordant for TD/CTD. Perinatal data were collected from the Medical Birth Register and TD/CTD diagnoses were collected from the National Patient Register, using a previously validated algorithm. In the fully adjusted models, impaired fetal growth, preterm birth, breech presentation and cesarean section were associated with a higher risk of TD/CTD, largely independent from shared family confounders and measured covariates. Maternal smoking during pregnancy was associated with risk of TD/CTD in a dose-response manner but the association was no longer statistically significant in the sibling comparison models or after the exclusion of comorbid attention-deficit/hyperactivity disorder. A dose-response relationship between the number of adverse perinatal events and increased risk for TD/CTD was also observed, with hazard ratios ranging from 1.41 (95% confidence interval (CI): 1.33-1.50) for one event to 2.42 (95% CI: 1.65-3.53) for five or more events. These results pave the way for future gene by environment interaction and epigenetic studies in TD/CTD.

Review of the evidence for the management of co-morbid Tic disorders in children and adolescents with attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in children and adolescents, with prevalence ranging between 5% and 12% in the developed countries. Tic disorders (TD) are common co-morbidities in paediatric ADHD patients with or without pharmacotherapy treatment. There has been conflicting evidence of the role of psychostimulants in either precipitating or exacerbating TDs in ADHD patients. We carried out a literature review relating to the management of TDs in children and adolescents with ADHD through a comprehensive search of MEDLINE, EMBASE, CINAHL and Cochrane databases. No quantitative synthesis (meta-analysis) was deemed appropriate. Meta-analysis of controlled trials does not support an association between new onset or worsening of tics and normal doses of psychostimulant use. Supratherapeutic doses of dextroamphetamine have been shown to exacerbate TD. Most tics are mild or moderate and respond to psychoeducation and behavioural management. Level A evidence support the use of alpha adrenergic agonists, including Clonidine and Guanfacine, reuptake noradrenenaline inhibitors (Atomoxetine) and stimulants (Methylphenidate and Dexamphetamines) for the treatment of Tics and comorbid ADHD. Priority should be given to the management of co-morbid Tourette’s syndrome (TS) or severely disabling tics in children and adolescents with ADHD. Severe TDs may require antipsychotic treatment. Antipsychotics, especially Aripiprazole, are safe and effective treatment for TS or severe Tics, but they only moderately control the co-occurring ADHD symptomatology. Short vignettes of different common clinical scenarios are presented to help clinicians determine the most appropriate treatment to consider in each patient presenting with ADHD and co-morbid TDs.

Psychiatric comorbidities in movement disorders

Psychiatric comorbidities are common in movement disorders. This review provides a practical approach to help clinicians to recognize psychiatric disorders in the most frequent movement disorders. However, the extent of neurodegeneration, as well as the impact of medications with considerable CNS effects, influences the diverse psychiatric presentations that, in turn, are influenced by the stress of living with a movement disorder. Depression, anxiety, and psychosis are the most common psychiatric comorbidities in movement disorders and of the medications used to treat the motor disturbances. These psychiatric problems impair patients' functioning throughout the course of the chronic neurodegenerative diseases. Due to the direct connection between brain dysfunction and psychiatric symptoms, there is hope that understanding the psychiatric comorbidities in movement disorders will lead to a better quality-of-life.

Tourette syndrome research highlights from 2016

This article presents highlights chosen from research that appeared during 2016 on Tourette syndrome and other tic disorders. Selected articles felt to represent meaningful advances in the field are briefly summarized.

Tourette syndrome research highlights from 2016

This article presents highlights chosen from research that appeared during 2016 on Tourette syndrome and other tic disorders. Selected articles felt to represent meaningful advances in the field are briefly summarized.

Genetic Approaches to Understanding Psychiatric Disease

Human genetic studies have been the driving force in bringing to light the underlying biology of psychiatric conditions. As these studies fill in the gaps in our knowledge of the mechanisms at play, we will be better equipped to design therapies in rational and targeted ways, or repurpose existing therapies in previously unanticipated ways. This review is intended for those unfamiliar with psychiatric genetics as a field and provides a primer on different modes of genetic variation, the technologies currently used to probe them, and concepts that provide context for interpreting the gene-phenotype relationship. Like other subfields in human genetics, psychiatric genetics is moving from microarray technology to sequencing-based approaches as barriers of cost and expertise are removed, and the ramifications of this transition are discussed here. A summary is then given of recent genetic discoveries in a number of neuropsychiatric conditions, with particular emphasis on neurodevelopmental conditions. The general impact of genetics on drug development has been to underscore the extensive etiological heterogeneity in seemingly cohesive diagnostic categories. Consequently, the path forward is not in therapies hoping to reach large swaths of patients sharing a clinically defined diagnosis, but rather in targeting patients belonging to specific "biotypes" defined through a combination of objective, quantifiable data, including genotype.

Association of Streptococcal Throat Infection With Mental Disorders: Testing Key Aspects of the PANDAS Hypothesis in a Nationwide Study

IMPORTANCE

Streptococcal infection has been linked with the development of obsessive-compulsive disorder (OCD) and tic disorders, a concept termed pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS). However, previous studies of this association have been small, and the results have been conflicting.

OBJECTIVE

To investigate the risk of mental disorders, specifically OCD and tic disorders, after a streptococcal throat infection.

DESIGN, SETTING, AND PARTICIPANTS

A population-based cohort study was conducted using data from the nationwide Danish registers from January 1, 1996, to December 31, 2013, with up to 17 years of follow-up. The Danish National Health Service Register provided information on individuals with the registration of a streptococcal test. Data analysis was conducted from January 1, 2016, to February 28, 2017.

MAIN OUTCOMES AND MEASURES

Individuals were followed up in the nationwide Psychiatric Central Register for a diagnosis of any mental disorder, OCD, or tic disorders. Incidence rate ratios (IRRs) were calculated by Poisson regression analysis.

RESULTS

Of the 1 067 743 children (<18 years of age) included in the study (519 821 girls and 547 922 boys), 638 265 received a streptococcal test, 349 982 of whom had positive test results at least once. Individuals with a positive streptococcal test result had an increased risk of any mental disorder (n = 15 408; IRR, 1.18; 95% CI, 1.15-1.21; P < .001), particularly of OCD (n = 556; IRR, 1.51; 95% CI, 1.28-1.77; P < .001) and tic disorders (n = 993; IRR, 1.35; 95% CI, 1.21-1.50; P < .001), compared with individuals without a streptococcal test. Furthermore, the risk of any mental disorder and OCD was more elevated after a streptococcal throat infection than after a nonstreptococcal infection. Nonetheless, individuals with a nonstreptococcal throat infection also had an increased risk of any mental disorder (n = 11 315; IRR, 1.08; 95% CI, 1.06-1.11; P < .001), OCD (n = 316; IRR, 1.28; 95% CI, 1.07-1.53; P = .006), and tic disorders (n = 662; IRR, 1.25; 95% CI, 1.12-1.41; P < .001).

CONCLUSIONS AND RELEVANCE

This large-scale study investigating key aspects of the PANDAS hypothesis found that individuals with a streptococcal throat infection had elevated risks of mental disorders, particularly OCD and tic disorders. However, nonstreptococcal throat infection was also associated with increased risks, although less than streptococcal infections for OCD and any mental disorder, which could also support important elements of the diagnostic concept of pediatric acute-onset neuropsychiatric syndrome.