Disentangling the effects of Tourette syndrome and attention deficit hyperactivity disorder on cognitive and behavioral phenotypes

Tics emergencies and malignant tourette syndrome: Assessment and management

Tourette syndrome (TS) is a complex neurodevelopmental disorder characterized by the presence of tics, frequently accompanied by a variety of neuropsychiatric comorbidities. A subset of patients with TS present with severe and disabling symptoms, requiring prompt therapeutic intervention. Some of these manifestations may result in medical emergencies when severe motor or phonic tics lead to damage of anatomical structures closely related to the tic. Examples include myelopathy or radiculopathy following severe neck ("whiplash") jerks or a variety of self-inflicted injuries. In addition to self-aggression or, less commonly, allo-aggression, some patients exhibit highly inappropriate behavior, suicidal tendencies, and rage attacks which increase the burden of the disease and are important components of "malignant TS". This subset of TS is frequently associated with comorbid obsessive-compulsive disorder. Therapeutic measures include intensive behavioral therapy, optimization of oral pharmacotherapy, botulinum toxin injections, and deep brain stimulation.

Comorbidities and Disease Duration in Tourette Syndrome: Impact on Cognition and Quality of Life of Children

BACKGROUND

Cognitive functions represent foundational factors for mental health and quality of life (QoL). In Tourette syndrome (TS), psychiatric comorbidities are common and have been inconsistently reported to affect the cognition and QoL of patients, while the role of tic disorder duration has not been yet explored.

METHODS

To examine how comorbidities and TS duration may influence cognition and QoL, N = 80 children with TS (6-16 years) were evaluated using the Wechsler Intelligence Scale for Children (WISC-IV). Standardized questionnaires were used to assess the presence and severity of TS main comorbidities and QoL. Data were interpreted using linear correlations, regression, and mediation analysis.

RESULTS

Depression and attention-deficit/hyperactivity disorder (ADHD) symptoms accounted for poorer cognitive performance. Anxiety oppositely predicted better cognitive performance, while no significant role for obsessive compulsive disorder (OCD) was observed. Disease duration was associated with lower total IQ, verbal reasoning, and working memory abilities. Depression, anxiety, and TS duration also deeply influenced QoL measures.

CONCLUSIONS

TS common comorbidities have a differential impact on the cognitive abilities of children and adolescents, which translates into a complex influence on their perceived QoL. A longer clinical history of tics was related to worse cognitive outcomes, which prompts further consideration of disease duration in both clinical and research settings involving children and adolescents.

Sociodemographic and clinical characteristics of children with tic disorders and behavioral problems: A real-world study and development of a prediction model

BACKGROUND

Tic disorders (TD) are complex neuropsychiatric disorders frequently associated with a variety of comorbid problems, whose negative effects may exceed those of the tics themselves. In this study, we aimed to explore the sociodemographic and clinical characteristics of children with TD and behavioral problems, and develop a prediction model of behavioral problems based on the predictors under real-world conditions.

METHODS

A hospital-based cross-sectional study was conducted on children with TD. Behavioral problems were surveyed using the Achenbach Child Behavior Checklist (CBCL). Sociodemographic information was collected from face-to-face interviews using an electronic questionnaire administered during the initial ambulatory visit. Clinical data were collected from medical records, and quality control was performed. The sociodemographic and clinical characteristics of patients with and without behavioral problems were statistically compared, and a nomogram prediction model was developed based on multivariate logistic regression analysis. The discriminatory ability and clinical utility of the nomogram were assessed by concordance index (C-index), receiver operating characteristic (ROC) curve, decision curve analysis (DCA) and clinical impact curve (CIC).

RESULTS

A total of 343 TD cases were included in the final analysis, of which 30.32% had behavioral problems. The prediction model showed age 12-16 years, abnormal birth history, parenting pattern of indulgence, parent/close relatives with psychiatric disorders, chronic motor or vocal tic disorder (CTD)/Tourette syndrome (TS) and moderate/severe tic severity were associated with behavioral problems in children with TD. The C-index of the prediction model (nomogram) was 0.763 (95% confidence interval, 0.710 ~ 0.816). The nomogram was feasible for making beneficial clinical decisions, according to the satisfactory results of the DCA and CIC.

CONCLUSIONS

A nomogram prediction model for comorbid behavioral problems in children with TD was established. The prediction model demonstrated a good discriminative ability and predictive performance for beneficial clinical decisions. This model further provides a comprehensive understanding of associated sociodemographic and clinical characteristics by visual graphs and allows clinicians to rapidly identify patients with a higher risk of behavioral problems and tailor necessary interventions to improve clinical outcomes.

WISC-IV performance of children with Chronic Tic Disorder, Obsessive-Compulsive Disorder and Attention-Deficit/Hyperactivity Disorder: results from a German clinical study

BACKGROUND

Chronic Tic Disorder (CTD), Obsessive-Compulsive Disorder (OCD) and Attention-Deficit/Hyperactivity Disorder (ADHD) are complex neuropsychiatric disorders that frequently co-occur. The aim of this study was to examine WISC-IV performance of a clinical cohort of children with CTD, OCD and/or ADHD.

METHODS

N = 185 children aged 6 to 17 years from Germany with CTD, OCD and/or ADHD were examined with the WISC-IV that comprises four index scores (VCI: Verbal Comprehension Index, PRI: Perceptual Reasoning Index, WMI: Working Memory Index, PSI: Processing Speed Index) and a Full Scale Intelligence Quotient (FSIQ). WISC-IV profiles of children with CTD-only, OCD-only, ADHD-only, CTD+ADHD, CTD+OCD and CTD+OCD+ADHD were compared with the WISC-IV norm (N = 1650, M = 100 and SD = 15) and among each other.

RESULTS

Unpaired t-tests revealed that children with ADHD-only showed significant lower PSI scores, whereas children with CTD-only and OCD-only had significant higher VCI scores as compared to the German WISC-IV norm. One-way ANOVA revealed that children with ADHD-only showed significant lower WMI scores as compared to children with CTD+OCD.

CONCLUSIONS

We were able to confirm previous evidence on WISC-IV profiles in ADHD in a German clinical sample and contribute new findings on cognitive performance in children with (non-)comorbid CTD and OCD that have to be seen in light of the study's limitations.

Comorbid chronic tic disorder and tourette syndrome in children requiring inpatient mental health treatment

OBJECTIVE

Children needing admission to an inpatient mental health unit often present with severe neuropsychiatric disorders characterised by complex psychopathology. We aimed to examine all admitted children with comorbid chronic tic disorder (CTD) and Tourette syndrome (TS) over a 10-year period and determine the clinical significance of these diagnoses.

METHOD

A retrospective, naturalistic study was conducted, comparing children with and without CTD/TS in terms of co-morbid diagnoses, medication use, access to education, aggression contributing to the admission, duration of admission, functional outcomes and satisfaction with treatment. Data were analysed using Chi-square/Fisher's exact test and t-test for categorical and continuous variables, respectively, and subsequently with unadjusted and adjusted linear and logistic regression analyses.

RESULTS

A relatively high proportion of children had co-morbid CTD/TS (19.7%). There was a significant association with co-morbid obsessive-compulsive disorder, intellectual disability and autism spectrum disorder but not attention deficit hyperactivity disorder. CTD/TS were associated with longer admissions even after adjustments for confounding but did not seem to be independently associated with other examined clinical characteristics.

CONCLUSIONS

The prevalence of CTD/TS in children needing inpatient treatment is significant. In our sample, comorbid CTD/TS seem to represent a marker of overall symptom severity as evidenced by longer admissions.

Is Persistent Motor or Vocal Tic Disorder a Milder Form of Tourette Syndrome?

Background

Persistent motor or vocal tic disorder (PMVT) has been hypothesized to be a forme fruste of Tourette syndrome (TS). Although the primary diagnostic criterion for PMVT (presence of motor or vocal tics, but not both) is clear, less is known about its clinical presentation.

Objective

The goals of this study were to compare the prevalence and number of comorbid psychiatric disorders, tic severity, age at tic onset, and family history for TS and PMVT.

Methods

We analyzed data from two independent cohorts using generalized linear equations and confirmed our findings using meta‐analyses, incorporating data from previously published literature.

Results

Rates of obsessive–compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) were lower in PMVT than in TS in all analyses. Other psychiatric comorbidities occurred with similar frequencies in PMVT and TS in both cohorts, although meta‐analyses suggested lower rates of most psychiatric disorders in PMVT compared with TS. ADHD and OCD increased the odds of comorbid mood, anxiety, substance use, and disruptive behaviors, and accounted for observed differences between PMVT and TS. Age of tic onset was approximately 2 years later, and tic severity was lower in PMVT than in TS. First‐degree relatives had elevated rates of TS, PMVT, OCD, and ADHD compared with population prevalences, with rates of TS equal to or greater than PMVT rates.

Conclusions

Our findings support the hypothesis that PMVT and TS occur along a clinical spectrum in which TS is a more severe and PMVT a less severe manifestation of a continuous neurodevelopmental tic spectrum disorder. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Clinical Correlates of Health-Related Quality of Life in Adults With Chronic Tic Disorder

Tics are the hallmark feature of Tourette syndrome (TS), but psychiatric and sensory symptoms are widely prevalent and increasingly recognized as core manifestations of the disorder. Accumulating evidence suggests that these psychiatric and sensory symptoms exert greater influence on quality of life (QOL) than tics themselves. However, much remains uncertain about determinants of QOL in TS due to the complexity of the clinical presentation. Here, we sought to clarify the association between health-related QOL (HRQOL) and common psychiatric and sensory symptoms in adults with TS and other chronic tic disorders. To do so, we prospectively recruited 52 patients from a tertiary care clinic to complete self-report measures assessing HRQOL (Gilles de la Tourette-Quality of Life Scale, GTS-QOL), depression (Patient Health Questionnaire-9, PHQ-9), anxiety (Generalized Anxiety Disorder Scale-7, GAD-7), obsessive-compulsive symptoms (Dimensional Obsessive-Compulsive Scale, DOCS), attention deficit hyperactivity disorder symptoms (Adult ADHD Self-Report Screening Scale for DSM-5, ASRS-V), and premonitory urge (Premonitory Urge to Tic Scale, PUTS). All participants were also administered the Yale Global Tic Severity Scale (YGTSS) to quantify tic severity. Using correlational analysis and multivariable linear regression modeling, we found that GTS-QOL score was significantly associated with scores from all other rating scales, with the exception of the PUTS. GTS-QOL was most strongly associated with PHQ-9, followed by ASRS-V, GAD-7, DOCS, and YGTSS total tic score. The regression model including these five independent variables, as well as sex, explained 79% of GTS-QOL score variance [F _(6,40) = 29.6, p < 0.001]. Specific psychiatric symptoms differentially impacted physical, psychological, and cognitive HRQOL. Systematic assessment of psychiatric comorbidities is imperative for clinical care and clinical research efforts directed at improving QOL in adults with chronic tic disorders.

Incidence of Autism Spectrum Disorder in Youths Affected by Gilles de la Tourette Syndrome Based on Data from a Large Single Italian Clinical Cohort

Gilles de la Tourette syndrome (GTS) and autism spectrum disorder (ASD) are etiologically related neurodevelopmental disorders with an onset age before 18 years and a reported comorbidity of 2.9–20%. The aim of the present study was to identify the incidence of ASD in a large clinical sample of individuals affected by GTS and to compare our results with previously reported incidences. We retrospectively analyzed clinical data (n = 1200) from January 2010 to March 2019 obtained from the outpatient Catania Tourette Clinic, part of the Child and Adolescent Neurology and Psychiatry of the Medical and Experimental Department of Catania University. We used internationally validated evaluation tools. The neuropsychological evaluation was carried out by an expert and a certificated team of child and adolescent neurologists, supervised by two expert child neurologists (R.R. and M.G.). We investigated 975 GTS-affected individuals of various socioeconomic levels aged 5–18 years, and 8.9% (n = 87) were affected by ASD. The incidence of GTS with ASD was significantly lower (p < 0.001) in children than in adolescents. No statistically significant differences were found in the sex distribution and age of onset of tics between individuals with GTS alone and those with GTS and ASD. The incidence of GTS and ASD comorbidity in this study was high, and this has several implications in terms of treatment and prognosis.

Clinical Features That Evoke the Concept of Disinhibition in Tourette Syndrome

The capacity to efficiently control motor output, by either refraining from prepotent actions or disengaging from ongoing motor behaviors, is necessary for our ability to thrive in a stimulus-rich and socially complex environment. Failure to engage in successful inhibitory motor control could lead to aberrant behaviors typified by an excess of motor performance. In tic disorders and Tourette syndrome (TS) - the most common tic disorder encountered in clinics - surplus motor output is rarely the only relevant clinical sign. A range of abnormal behaviors is often encountered which are historically viewed as "disinhibition phenomena". Here, we present the different clinical features of TS from distinct categorical domains (motor, sensory, complex behavioral) that evoke the concept of disinhibition and discuss their associations. We also present evidence for their consideration as phenomena of inhibitory dysfunction and provide an overview of studies on TS pathophysiology which support this view. We then critically dissect the concept of disinhibition in TS and illuminate other salient aspects, which should be considered in a unitary pathophysiological approach. We briefly touch upon the dangers of oversimplification and emphasize the necessity of conceptual diversity in the scientific exploration of TS, from disinhibition and beyond.

Gilles de la Tourette Syndrome, Depression, Depressive Illness, and Correlates in a Child and Adolescent Population

OBJECTIVE

Gilles de la Tourette syndrome (GTS) and depression are both common disorders. It has been suggested that depression occurs in 13%-76% GTS patients. Despite this, there are few studies into the specific relationships and correlates between the two disorders. There is only some consensus as to the precise relationship between the two disorders.

MATERIALS AND METHODS

We undertook the study to investigate the relationship between depressive symptomatology and the core clinical features of GTS in a well-characterized clinical population of youth with this disorder. Our aim was to verify the association between depression and comorbid obsessive-compulsive disorder and explore further other potential associations highlighted in some, but not all, of the studies focused on this topic.

RESULTS

Our results demonstrated that (1) the GTS patients were significantly older than the controls, (2) the GTS patients were significantly more depressed than controls, (3) depression was associated with tic severity, (4) the Diagnostic Confidence Index scores were higher in GTS patients without depression, (5) anxiety, attention-deficit/hyperactivity disorder (ADHD), conduct disorder (CD), and behavioral problems were significantly associated with depression, and (6) finally, patients with GTS and depression have a positive family history of depression. However, obsessionality (CY-BOCS) did not differentiate between depressed and not depressed GTS patients.

CONCLUSIONS

Depression is common in patients with GTS and occurs significantly more in GTS than in controls. Depression is significantly associated with GTS factors such as tic severity, comorbidity with ADHD, and the presence of coexistent anxiety, CDs, and behavior problems. Depression is importantly significantly associated with a positive family history of depression. Intriguingly, depression in our sample was not related to obsessionality.

The impact of adjunctive guanfacine extended release on stimulant adherence in children/adolescents with attention-deficit/hyperactivity disorder

Aim: To assess stimulant adherence among children/adolescents with attention-deficit/hyperactivity disorder (ADHD) augmenting stimulants with guanfacine extended-release (GXR). Patients & methods: Inclusion criteria: 6–17 years, ≥1 ADHD diagnosis, ≥1 long-acting and/or short-acting stimulant with GXR augmentation. Modified medication possession ratio (mMPR; days medication available/days in period, excluding medication holidays) was assessed; mMPR <0.80 nonadherent. Regression models assessed change in mMPR adjusting for demographic and clinical characteristics. Results: Among patients nonadherent to stimulants pre-augmentation (n = 165), unadjusted mean (SD) pre- and post-stimulant mMPRs were 0.68 (0.11) and 0.87 (0.16). Adjusted mean change in mMPR was 0.20 for long-acting versus 0.18 for short-acting stimulants (p = 0.34). Conclusion: Among patients nonadherent to stimulants, GXR augmentation was associated with increased stimulant adherence.

Putting the Pieces Together in Gilles de la Tourette Syndrome: Exploring the Link Between Clinical Observations and the Biological Basis of Dysfunction

Gilles de la Tourette syndrome is a complex, idiopathic neuropsychiatric disorder whose pathophysiological mechanisms have yet to be elucidated. It is phenotypically heterogeneous and manifests more often than not with both motor and behavioral impairment, although tics are its clinical hallmark. Tics themselves present with a complex profile as they characteristically wax and wane and are often preceded by premonitory somatosensory sensations to which it is said a tic is the response. Highly comorbid with obsessive-compulsive disorder and attention deficit-hyperactivity disorder, it is purported to be an epigenetic, neurodevelopmental spectrum disorder with a complex genetic profile. It has a childhood onset, occurs disproportionately in males, and shows spontaneous symptomatic attenuation by adulthood in the majority of those afflicted. Although not fully understood, its neurobiological basis is linked to dysfunction in the cortico-basal ganglia-thalamo-cortical network. Treatment modalities for Tourette syndrome include behavioral, pharmacological and surgical interventions, but there is presently no cure for the disorder. For those severely affected, deep brain stimulation (DBS) has recently become a viable therapeutic option. A key factor to attaining optimal results from this surgery is target selection, a topic still under debate due to the complex clinical profile presented by GTS patients. Depending on its phenotypic expression and the most problematic aspect of the disorder for the individual, one of three brain regions is most commonly chosen for stimulation: the thalamus, globus pallidus, or nucleus accumbens. Neurophysiological analyses of intra- and post-operative human electrophysiological recordings from clinical DBS studies suggest a link between tic behavior and activity in both the thalamus and globus pallidus. In particular, chronic recordings from the thalamus have shown a correlation between symptomatology and (1) spectral activity in gamma band power and (2) theta/gamma cross frequency coherence. These results suggest gamma oscillations and theta/gamma cross correlation dynamics may serve as biomarkers for dysfunction. While acute and chronic recordings from human subjects undergoing DBS have provided better insight into tic genesis and the neuropathophysiological mechanisms underlying Tourette syndrome, these studies are still sparse and the field would greatly benefit from further investigations. This review reports data and discoveries of scientific and clinical relevance from a wide variety of methods and provides up-to-date information about our current understanding of the pathomechanisms underlying Tourette syndrome. It gives a comprehensive overview of the current state of knowledge and addresses open questions in the field.

The English Version of the Gilles de la Tourette Syndrome-Quality of Life Scale for Children and Adolescents (C&A-GTS-QOL)

Gilles de la Tourette syndrome is a chronic neuropsychiatric disorder that can have a detrimental impact on the health-related quality of life of children with the condition. To date no patient-reported health-related quality of life measures have been developed for children and adolescents in the English language. This study validated the first disease-specific scale for the quantitative assessment of health-related quality of life in 118 children and adolescents with Gilles de la Tourette syndrome (C&A-GTS-QOL) following language adaptation from Italian to English in the United Kingdom. Standard statistical methods were used to test the psychometric properties of the rating scale. Principal component factor analyses led to the identification of six health-related quality of life domains (cognitive, copro-phenomena, psychological, physical, obsessive-compulsive, and activities of daily living), explaining 66.7% of the overall variance. The C&A-GTS-QOL demonstrated satisfactory scaling assumptions and acceptability; validity was supported by interscale correlations (range 0.2-0.7), confirmatory factor analysis, and correlation patterns with other rating scales and clinical variables.

Tourette Syndrome and Comorbid Neuropsychiatric Conditions

Tourette syndrome is a neuropsychiatric condition characterized by both motor and phonic tics over a period of at least 1 year with the onset in childhood or adolescence. Apart from the tics, most of the patients with Tourette syndrome have associated neuropsychiatric comorbidities consisting of attention deficit hyperactivity disorder, obsessive compulsive disorder, rage attacks, sleep issues, depression, and migraine. Patients may also have physical complications directly from violent motor tics which can rarely include cervical myelopathy, arterial dissection, and stroke. The purpose of this article is to review the associated neuropsychiatric comorbidities of Tourette syndrome with emphasis on recent research.

Clinical effectiveness and patient perspectives of different treatment strategies for tics in children and adolescents with Tourette syndrome: a systematic review and qualitative analysis

BACKGROUND

Tourette syndrome (TS) is a neurodevelopmental condition characterised by chronic motor and vocal tics affecting up to 1% of school-age children and young people and is associated with significant distress and psychosocial impairment.

OBJECTIVE

To conduct a systematic review of the benefits and risks of pharmacological, behavioural and physical interventions for tics in children and young people with TS (part 1) and to explore the experience of treatment and services from the perspective of young people with TS and their parents (part 2).

DATA SOURCES

For the systematic reviews (parts 1 and 2), mainstream bibliographic databases, The Cochrane Library, education, social care and grey literature databases were searched using subject headings and text words for tic* and Tourette* from database inception to January 2013.

REVIEW/RESEARCH METHODS

For part 1, randomised controlled trials and controlled before-and-after studies of pharmacological, behavioural or physical interventions in children or young people (aged < 18 years) with TS or chronic tic disorder were included. Mixed studies and studies in adults were considered as supporting evidence. Risk of bias associated with each study was evaluated using the Cochrane tool. When there was sufficient data, random-effects meta-analysis was used to synthesize the evidence and the quality of evidence for each outcome was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. For part 2, qualitative studies and survey literature conducted in populations of children/young people with TS or their carers or in health professionals with experience of treating TS were included in the qualitative review. Results were synthesized narratively. In addition, a national parent/carer survey was conducted via the Tourettes Action website. Participants included parents of children and young people with TS aged under 18 years. Participants (young people with TS aged 10-17 years) for the in-depth interviews were recruited via a national survey and specialist Tourettes clinics in the UK.

RESULTS

For part 1, 70 studies were included in the quantitative systematic review. The evidence suggested that for treating tics in children and young people with TS, antipsychotic drugs [standardised mean difference (SMD) -0.74, 95% confidence interval (CI) -1.08 to -0.41; n = 75] and noradrenergic agents [clonidine (Dixarit(®), Boehringer Ingelheim) and guanfacine: SMD -0.72, 95% CI -1.03 to -0.40; n = 164] are effective in the short term. There was little difference among antipsychotics in terms of benefits, but adverse effect profiles do differ. Habit reversal training (HRT)/comprehensive behavioural intervention for tics (CBIT) was also shown to be effective (SMD -0.64, 95% CI -0.99 to -0.29; n = 133). For part 2, 295 parents/carers of children and young people with TS contributed useable survey data. Forty young people with TS participated in in-depth interviews. Four studies were in the qualitative review. Key themes were difficulties in accessing specialist care and behavioural interventions, delay in diagnosis, importance of anxiety and emotional symptoms, lack of provision of information to schools and inadequate information regarding medication and adverse effects.

LIMITATIONS

The number and quality of clinical trials is low and this downgrades the strength of the evidence and conclusions.

CONCLUSIONS

Antipsychotics, noradrenergic agents and HRT/CBIT are effective in reducing tics in children and young people with TS. The balance of benefits and harms favours the most commonly used medications: risperidone (Risperdal(®), Janssen), clonidine and aripiprazole (Abilify(®), Otsuka). Larger and better-conducted trials addressing important clinical uncertainties are required. Further research is needed into widening access to behavioural interventions through use of technology including mobile applications ('apps') and video consultation.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42012002059.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Treatment-refractory Tourette Syndrome

Tourette Syndrome (TS) is a complex neurodevelopmental condition marked by tics and frequently associated with psychiatric comorbidities. While most cases are mild and improve with age, some are treatment-refractory. Here, we review strategies for the management of this population. We begin by examining the diagnosis of TS and routine management strategies. We then consider emerging treatments for refractory cases, including deep brain stimulation (DBS), electroconvulsive therapy (ECT), repetitive transcranial magnetic stimulation (rTMS), and novel pharmacological approaches such as new vesicular monoamine transporter type 2 inhibitors, cannabinoids, and anti-glutamatergic drugs.

Circulating miRNAs profiles in Tourette syndrome: molecular data and clinical implications

BACKGROUND

Tourette Syndrome (TS) is a highly prevalent childhood neuropsychiatric disorder (about 1 %), characterized by multiple motor and one or more vocal tics. The syndrome is commonly associated to comorbid conditions (e.g., Attention Deficit Hyperactivity Disorder and Obsessive Compulsive Disorder), which considerably aggravate clinical symptoms and complicate diagnosis and treatment. To date, TS molecular bases are unknown and its molecular diagnosis is unfeasible.

RESULTS

Due to their master role within cell networks and pathways both in physiology as in pathology, we sought to determine the transcriptome of circulating miRNAs in TS patients: by TaqMan Low Density Arrays, we profiled the expression in serum of 754 miRNAs in six TS patients and three unaffected controls (NCs) (discovery set). These data were validated by single TaqMan assays on serum from 52 TS patients and 15 NCs (validation set). Network and Gene-ontology analysis were performed by using Cytoscape and Babelomics server. We found that miR-429 is significantly underexpressed in TS patients with respect to NCs. Decreased serum levels of miR-429 allowed us to discriminate TS patients from NCs with 95 % of sensitivity and 42 % of specificity. Intriguingly, computational analysis of the network comprising miR-429 targets demonstrates their involvement in differentiation of midbrain and hindbrain and synaptic transmission.

CONCLUSIONS

Our data open the way to further molecular characterization of TS and eventual identification of the corresponding genotypes. Circulating miR-429 may be immediately useful as sensitive molecular biomarker to support TS diagnosis, actually based only on DSM-V criteria.

Tourette syndrome and comorbid ADHD: causes and consequences

Attention deficit hyperactivity disorder (ADHD) is the most common comorbid condition in patients with Tourette syndrome (TS). The co-occurrence of ADHD and TS is in most cases associated with a higher social and psychopathological impairment. Comorbidity between Tourette and ADHD appears to have a complex and partially known pathogenesis in which genetic, environmental, and neurobiological factors can be implicated. Genetic studies have revealed an involvement of dopaminergic, catecholaminergic, and GABAergic genes that modulated the activity of neurotransmitters. Furthermore, there are a lot of networks implicated in the development of ADHD and TS, involving cortical and striatal areas and basal ganglia. Although a large number of studies tried to find a common pathogenesis, the complex pathways responsible are not clear. The genes implicated in both disorders are currently unidentified, but it is probable that epigenetic factors associated with neural modifications can represent a substrate for the development of the diseases.

CONCLUSION

In this paper, recent advances in neurobiology of ADHD and TS are reviewed, providing a basis for understanding the complex common pathogenesis underlying the frequent co-occurrence of the two conditions and the therapeutic choices.

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.

Tourette syndrome and comorbid conditions: a spectrum of different severities and complexities

To investigate clinical correlates of Tourette syndrome and to identify the impact of comorbidities, we retrospectively recruited 92 young people affected by Tourette syndrome compared with 102 healthy controls. Neuropsychological assessment included: Youth Quality of Life-Research, Multidimensional Anxiety Scale for Children, Children's Depression Inventory, and Conner's and Child Behavior Checklist; moreover, Tourette syndrome patients completed the Yale Global Tic Severity Rating Scale and the Yale-Brown Obsessive Compulsive Scale. Four clinical subgroups were identified: pure Tourette syndrome (49.8%), Tourette syndrome plus attention-deficit hyperactivity disorder (ADHD) (22.2%), Tourette syndrome plus obsessive-compulsive disorder (21.5%), and Tourette syndrome plus ADHD plus obsessive-compulsive disorder (6.5%). Our findings suggested that emotional lability appeared in all Tourette syndrome subgroups, independently from comorbidities, representing a clinical feature of Tourette syndrome itself. Moreover, our data suggested that all 4 clinical subgroups had higher statistically significant behavioral problems compared with the healthy controls (P = .000), whereas affective and anxiety symptoms were overrepresented in Tourette syndrome plus comorbidities subgroups. Finally, Tourette syndrome patients had a lower quality of life compared with the healthy controls. These differences were statistically significant between the pure Tourette syndrome subgroups and Tourette syndrome plus comorbidities subgroups, as well as Tourette syndrome plus comorbidities subgroups and healthy controls.

Tourette syndrome is associated with insecure attachment and higher aggression

This study explored the degree to which adult patients with Tourette syndrome (TS) exhibit particular attachment styles and the possible association between the underlying attachment dimensions and forms of aggression. Fifty-three TS patients (ages 17-72 years) and 54 matched healthy controls completed the Experiences in Close Relationships-Revised Scale (ECR-R) and the Aggression Questionnaire (AQ). The data were analysed with ANOVA F-tests, t-tests, and Pearson's correlation coefficient. TS patients showed significantly higher scores in relationship anxiety ( p < 0.001) and relationship avoidance ( p = 0.001) in the ECR-R and significantly higher aggression scores in the AQ ( p < 0.001). The total AQ score correlated significantly with the ECR-R dimension anxiety ( p < 0.001). These are the first findings on TS patients' attachment styles and anger symptoms. It remains unclear whether attachment anxiety and avoidance are risk factors for TS or whether the disorder itself induces attachment disorders. Prospective studies with detailed attachment interviews would help to explore this issue.

Tourette Syndrome and comorbid ADHD: current pharmacological treatment options

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is the most common co-morbid condition encountered in people with tics and Tourette Syndrome (TS). The co-occurrence of TS and ADHD is associated with a higher psychopathological, social and academic impairment and the management may represent a challenge for the clinicians.

AIM

To review recent advances in management of patients with tic, Tourette Syndrome and comorbid Attention Deficit Hyperactivity Disorder.

METHODS

We searched peer reviewed and original medical publications (PUBMED 1990-2012) and included randomized, double-blind, controlled trials related to pharmacological treatment for tic and TS used in children and adolescents with comorbid ADHD. "Tourette Syndrome" or "Tic" and "ADHD", were cross referenced with the words "pharmacological treatment", "α-agonist", "psychostimulants", "selective norepinephrine reuptake inhibitor", "antipsychotics".

RESULTS

Three classes of drugs are currently used in the treatment of TS and comorbid ADHD: α-agonists (clonidine and guanfacine), stimulants (amphetamine enantiomers, methylphenidate enantiomers or slow release preparation), and selective norepinephrine reuptake inhibitor (atomoxetine). It has been recently suggested that in a few selected cases partial dopamine agonists (aripiprazole) could be useful.

CONCLUSION

Level A of evidence supported the use of noradrenergic agents (clonidine). Reuptake inhibitors (atomoxetine) and stimulants (methylphenidate) could be, also used for the treatment of TS and comorbid ADHD. Taking into account the risk-benefit profile, clonidine could be used as the first line treatment. However only few studies meet rigorous quality criteria in terms of study design and methodology; most trials have low statistical power due to small sample size or short duration. Treatment should be "symptom targeted" and personalized for each patient.

Tic Disorders and Learning Disability: Clinical Characteristics, Cognitive Performance and Comorbidity

Tics are involuntary movements or sounds. Tourette syndrome is one of a family of tic disorders that affect around 1% of the population but which remains underrecognised in the community. In paediatric special education learning disability classes, the prevalence of individuals with tic disorders is around 20–45% — higher still in special education emotional/behavioural classes. Given the high rates of individuals with tic disorders in special education settings, as well as the unique challenges of working in an educational setting with a person with a tic disorder, it is incumbent upon professionals working in these settings to be cognisant of the possibility of tic disorders in this population. This review seeks to provide an overview of tic disorders and their association with learning and mental health difficulties. The review focuses on an exploration of factors underpinning the association between tic disorders and learning disabilities, including neurocognitive corollaries of tic disorders and the influence of common comorbidities, such as ADHD, as well as upon strategies to support individuals with tic disorders in the classroom.

The psychopathological spectrum of Gilles de la Tourette syndrome

Gilles de la Tourette syndrome (GTS) holds a unique status as quintessentially neuropsychiatric condition at the interface between neurology (movement disorder) and psychiatry (behavioural condition). This is a reflection of the common observation that the vast majority of patients present with behavioural problems in association with the motor and vocal tics which define GTS. The present article focuses on the relationship between GTS and obsessive-compulsive disorder (OCD), attention-deficit and hyperactivity disorder (ADHD), affective disorders (both major depression and bipolar affective disorder), and personality disorders. Over the last decade, converging lines of research have pointed towards the concept of a 'GTS spectrum', encompassing motor phenomena and behavioural symptoms, with important implications for the clinical management of patients.

Long term clinical course of Tourette syndrome

BACKGROUND

Recent studies using cluster analysis and factor analysis have suggested that Tourette Syndrome (TS) should no longer be considered a unitary condition.

MATERIAL AND METHODS

We retrospectively studied the long term clinical course of 100 TS patients. The patients were assessed at the onset and after 10 years follow-up to evaluate the severity of tic, the Obsessive Compulsive Disorder (OCD), the Attention Deficit Hyperactivity Disorder (ADHD) and the presence of anxiety and depression, rage attacks, self injuries behavior. Moreover at the follow-up they completed an evaluation scale on quality of life to assess the impairment in everyday life after 10 years of illness.

RESULTS

The "pure TS" clinical group (38 subjects) showed after 10 years follow-up that 58% carried on with the same clinical phenotype, whereas 42% changed in "TS+OCD" phenotype. Fifty-five percentage required pharmacological treatment. All the "TS+ADHD" clinical group (48 subjects) showed after 10 years follow-up a different clinical phenotype: 62% "TS pure" phenotype, 35% "TS+OCD" phenotype, 2% "TS+ADHD+OCD" phenotype. Sixty-five percentage of the subject required pharmacological treatment. The "TS+ADHD+OCD" clinical group (14 subjects) after 10 years follow-up showed that 14% carried on with the same clinical phenotype, whereas 8.3% presented "TS pure" phenotype and 92% presented "TS+OCD" phenotype. Seventy-one percentage were in need of therapy. With regards to quality of life, patients presented widespread impairment correlated to the presence of comorbid conditions.

CONCLUSION

Our findings suggest that pure TS has quite a good long-term clinical course. By contrast, those who presented comorbid condition at the onset showed a more severe prognosis.

Prevalence and clinical correlates of tic disorders in a community sample of school-age children

To examine the prevalence, clinical characteristics and course of children with tics identified in a community sample. This was a three-stage study. At the age of 9 to 11, parents of 8,244 children born at Aarhus University Hospital Skejby between January 1990 and April 1992 were invited to complete a screening questionnaire about tics. One year later participating parents completed the Strengths and Difficulties Questionnaire (SDQ). From December 2004 to June 2005, when the cohort was 13-15 years of age, parents of the children who screened positive for tics were interviewed in detail about tic disorders. The prevalence of Tourette Syndrome (TS) was 0.6 and 0.6% of chronic motor tics (CMT). Approximately one-third of those with a chronic tic disorder [CTD (TS and CMT)] reported remission of tics by age 13-15. On the parent-rated SDQ children with a CTD were five times more likely (OR = 5.0, 95% CI = 2.6-9.2) to fall into the clinical range of hyperactivity, twice as likely (OR = 2.2, 95% CI = 2.1-7.5) to exhibit disruptive and defiant behavior and over four times more likely to have emotional difficulties (OR = 4.7, 95% CI = 2.5-8.6) compared to children without tic disorders. Children with hyperactivity and CTD were more impaired than subjects with CTD only. Children with CTD and hyperactivity show greater symptom severity across several domains of behavior and overall impairment. In the absence of hyperactivity, children with CTD are at increased risk for emotional difficulties, but not disruptive behavior problems.

Clinical phenomenology and phenotype variability in Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder with a rich phenomenology that includes simple and complex motor and vocal tics as well as multiple comorbidities. From a nosological perspective, it is evident that a continuum of tic severity exists, of which TS is the most severe and rare form, while transient tics and chronic tics represent milder forms. From a psychopathology perspective, TS is often concurrent with obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD); these disorders appear to define TS "types" TS only, TS+OCD, and TS+OCD+ADHD. Additional clinical aspects of TS include more frequent than expected occurrence of anger episodes, anxiety disorders, mood disorders, impulse control disorders, learning disorders, and pervasive developmental disorders. Data reduction techniques have been used more recently to define a "simple" and "complex" tic symptom clusters or factors. Phenomenologic approaches can be used in TS to guide future pathophysiologic research.

Anxiety in boys with attention-deficit/hyperactivity disorder with and without chronic multiple tic disorder

OBJECTIVE

This study examined the psychosocial and behavioral concomitants of anxiety in clinic-referred boys with attention-deficit/hyperactivity disorder (ADHD) with and without chronic multiple tic disorder (CMTD).

METHOD

ADHD boys with (n = 65) and without (n = 94) CMTD were evaluated with measures of psychiatric symptoms, mental health risk factors, and academic and social performance.

RESULTS

Boys with CMTD evidenced more severe anxiety and less social competence and were more likely to be living with only one biological parent than the ADHD Only group, but the magnitude of group differences was generally small. The severity of generalized anxiety, separation anxiety, social phobia, and obsessive-compulsive symptoms were uniquely associated with a different pattern of risk factors, and there was some evidence that these patterns differed for the two groups of boys.

CONCLUSION

Boys with CMTD had a relatively more severe and complex pattern of anxiety that was associated with different clinical features, all of which suggests that ADHD plus CMTD might better be conceptualized as a distinct clinical entity from ADHD Only. However, findings from the extant literature are mixed, and therefore this remains a topic for further study.

Adults with Tourette's syndrome with and without attention deficit hyperactivity disorder

OBJECTIVE

Comorbidity between Tourette's syndrome (TS) and attention deficit hyperactivity disorder (ADHD) is high. In children, those with both TS+ADHD fare less well than those with TS-only on measures of both psychopathology and behaviour. The objective of this study was to document such measures in adult patients.

METHOD

Eighty adults with TS-only were compared to 64 with TS+ADHD using a clinical interview and standardised measures of depression, anxiety and obsessionality.

RESULTS

The two groups were no different on measures of TS severity. TS+ADHD patients had significantly more depression, anxiety, obsessive-compulsive behaviour and maladaptive behaviours than patients with TS-only. There were also significant differences in the incidence of copro- and echo-phenomena and family history of ADHD.

CONCLUSION

The finding of increased overall behavioural difficulties and psychopathology in adult patients with TS+ADHD when compared with TS-only is in agreement with previous findings in children with TS. Appropriate treatment of ADHD in TS patients during childhood may prevent many behavioural problems in adulthood.

Tourette syndrome-associated psychopathology: roles of comorbid attention-deficit hyperactivity disorder and obsessive-compulsive disorder

OBJECTIVE

Individuals with Tourette syndrome (TS) often display comorbid symptoms of attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD), as well as externalizing and internalizing behaviors. This study was aimed to examine the impacts of tic severity, ADHD symptoms, and OCD on internalizing (e.g., anxiety) and externalizing (e.g., aggression) psychopathology.

METHODS

Using linear regressions, we examined how tics, ADHD, and OCD symptoms predicted the externalization and internalization behaviors measured by the Child Behavior Checklist in a clinical sample of children and adolescents with TS. In addition, Child Behavior Checklist scales were compared among children with TS without ADHD, TS and ADHD, ADHD without TS, and unaffected control group.

RESULTS

In the TS group, externalizing behaviors were predicted by tic severity, inattention, and hyperactivity/impulsivity but not by OCD symptoms, whereas internalizing behaviors were predicted by inattention and OCD symptoms but not by tic severity or hyperactivity/impulsivity. Comparison among different clinical groups revealed main effects of TS and ADHD on both externalizing and internalizing behaviors.

CONCLUSION

These findings suggest that tics, ADHD, and OCD symptoms differentially explain the variance in externalizing and internalizing behavioral problems in individuals with TS. In addition, the data support the notion that TS is itself a risk factor for behavioral problems, mandating that children with TS even without ADHD and OCD still need to be assessed and treated for psychopathology.

Psychiatric disorders and behavioral problems in children and adolescents with Tourette syndrome

OBJECTIVE

Many previous studies have surveyed associations between Tourette syndrome (TS) and co-morbid psychiatric disorders, but they usually did not include oppositional defiant disorder (ODD), conduct disorder (CD), separation anxiety disorder (SAD), and post-traumatic stress disorder (PTSD).

METHOD

The subjects were children and adolescents with TS who visited a child and adolescent psychiatric clinic, and who were interviewed using DSM-IV diagnostic criteria. Characteristics of their tics were examined by the Yale-Global Tic Severity Scale (Y-GTSS). Behavioral problems were surveyed by the Child Behavior Checklist (CBCL) filled in by the parents.

RESULTS

About 87.9% of the subjects were boys. The mean age of the subjects was 11.8 years. The most common psychiatric disorders were attention deficit hyperactivity disorder (ADHD), ODD, nail biting, and obsessive compulsive disorder (OCD). Only one subject was affected by TS without co-morbidities. Among TS patients with co-morbidities, those with disruptive behavioral disorders (DBD) have significantly higher mean scores than patients without DBD on the Externalizing scale, Social problems, Attention problems, Delinquent and Aggression scales. Co-morbidity of anxiety disorders was not related to the CBCL scores.

CONCLUSION

Many of our results were similar to those reported in studies conducted in other parts of the world. TS is more common in boys and nearly all of them had at least one co-morbid disorder. The most common co-morbidity was ADHD. Behavioral problems in TS are related to the co-morbidity with the DBD, and possibly not to the anxiety disorders.

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

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

Latent class analysis of gilles de la tourette syndrome using comorbidities: clinical and genetic implications

BACKGROUND

Although susceptibility loci exist for Gilles de la Tourette syndrome (GTS), no causative gene has been identified, perhaps in part because of phenotypic heterogeneity. This study used latent class analyses (LCA) to identify GTS subphenotypes and assess characteristics and heritability of the classes.

METHODS

The study included 952 individuals from 222 GTS families recruited for genetic studies. LCA identified a best-fit model for combinations of the diagnoses of GTS, obsessive-compulsive disorder (OCD), OC symptoms and behaviors (OCS/OCB), and attention-deficit/hyperactivity disorder (ADHD) in a random sample of one sibling from each family (n = 197), a replication sample randomly chosen from the remaining siblings (n = 203), and in the entire sample (all siblings and parents, N = 952). Heritabilities were assessed for all categoric diagnoses and LCA classes using a variance components approach.

RESULTS

In this large sample of GTS sib pairs and their parents, three GTS-affected groups were identified-GTS + OCS/OCB (Class III), GTS + OCD (Class IV), and GTS + OCD + ADHD (Class V)-in addition to a minimally affected class (I) and a small chronic tics + OCD class (II). A preponderance of males and younger age at onset was found in more comorbidly affected classes. Only the GTS + OCD + ADHD class was highly heritable.

CONCLUSIONS

Our data suggest that GTS classes may represent distinct entities, with both shared and unique etiologies. In particular, GTS + OCD + ADHD may represent a separate, heritable phenotype that can be used to further inform genetic studies.

Intra-individual variability in ADHD, autism spectrum disorders and Tourette's syndrome

The potential for response variability to serve as an endophenotype for attention deficit hyperactivity disorders (ADHD) rests, in part, upon the development of reliable and valid methods to decompose variability. This study investigated the specificity of intra-individual variability (IIV) in 53 children with ADHD by comparing them with 25 children with high functioning autism (HFA), 32 children with autism spectrum disorders (ASD), who also were comorbid for ADHD (ASD+ADHD), 21 children with Tourette's syndrome (TS), and 85 typically developing controls (TD). In order to decompose the variability of the reaction times, we applied three distinct techniques: ex-Gaussian modeling, intra-individual variability analysis, and spectral analysis. Our data revealed that children with HFA and children with ASD+ADHD exhibited substantial IIV compared with ADHD and TD children. We argue that: (1) all three methods lead to a single consistent conclusion; (2) careful documentation of the analytic steps used in spectral analysis is mandatory for comparison between studies; (3) the presence of comorbidities may constitute an important factor in the observed response variability in previous studies of ADHD.

Attentional functions in children and adolescents with attention-deficit/hyperactivity disorder with and without comorbid tic disorder

Although the coexistence of attention-deficit/hyperactivity disorder (ADHD) and tic disorder (TD) is common, the nature of association is yet not fully understood. Thus, the aim of the present study was to explore attentional dysfunction in children with pure ADHD compared to children with comorbid ADHD + TD. Three groups of 20 children each, aged 8-15 years with either ADHD, ADHD + chronic tic disorder or Tourette syndrome (ADHD + TD) and a healthy control group were compared in their performance on three computerized attention tasks. Tasks of sustained attention, selective attention and interference control were employed. In addition, parental ratings of ADHD symptom severity and behaviour problems were obtained. Both clinical groups were rated as equally inattentive, however, externalising symptoms were more severe in the ADHD group. Objective measures of attentional performance revealed differences between the groups: whereas the ADHD group was markedly impaired in sustaining attention and selective attention/inhibitory control, the ADHD + TD group only showed marginal deficits in selective attention/inhibitory control. Possible explanations for the superior performance of the comorbid group are discussed: In particular, the results may indicate that in some patients, the tic disorder produces behavioural symptoms of ADHD, but not the broad neurocognitive deficits that usually are associated with ADHD. Alternatively, compensatory neural mechanisms of TD patients may result in a better neuropsychological performance of comorbid patients relative to patients suffering from pure ADHD.