Childhood Comorbidity Severity Impacts Adolescent Substance Consumption in Patients With Tourette Syndrome.

BACKGROUND: This study explores the longitudinal impact of severity of Tourette Syndrome (TS), diagnosis and severity of Attention-Deficit/Hyperactivity Disorder (ADHD) and Obsessive-Compulsive Disorder (OCD), and guardian socioeconomic status on the level of substance use of pediatric patients with TS. METHODS: A total of 314 pediatric patients with TS participated at time 1 (T1). During these visits, the severity of the patients' TS, ADHD, and OCD symptoms were assessed, along with their guardians' socioeconomic status. At time 2 (T2), between four and eight years later (median 5.6 years), 227 patients returned for a follow-up. Here, the patients answered questions about their intake of alcohol, cigarettes, and illegal substances. The relationship between the patients' diagnoses, symptom severity, and socioeconomic status at T1 and reported substance use at T2 was then analyzed using binary logistic regression. RESULTS: Increased severity of ADHD and lower guardian socioeconomic status at T1 significantly increased the odds of later high cigarette consumption. Furthermore, both presence and increased severity of ADHD at T1 increased the odds of illegal substance consumption at T2. Conversely, increased severity of OCD at T1 significantly decreased cigarette and illegal substance consumption at T2, whereas both presence and increased severity of OCD decreased alcohol consumption. CONCLUSIONS: Pediatric patients with TS with increased ADHD severity have increased risk of consuming illegal substances and high amounts of cigarettes as adolescents, whereas increased OCD severity may act as a protective factor. Having preventative conversations about substance consumption with patients with TS with high ADHD severity is important.

Fine Motor Skills in Children with Tourette Syndrome and their Unaffected First-degree Siblings.

Background: The exact etiology of Tourette Syndrome (TS) remains unclear, making the search for impaired neuropsychological functions possibly connected to the underlying cause of TS as important as it is challenging. One neuropsychological domain of interest is fine motor skills. Method: This study compared fine motor skill performance on the Purdue Pegboard Task (PPT) in 18 children with TS, 24 unaffected first-degree siblings and 20 controls. A set of screening questionnaires was administered to determine comorbid psychiatric illness. Results: Children with TS, their siblings and controls did not differ significantly in fine motor skills as measured with the PPT. Performance on the PPT was not correlated with tic severity; however, we found an inverse correlation with severity of attention-deficit/hyperactivity disorder (ADHD) symptoms, as assessed by parent reported ADHD symptoms. Children with TS were found to have significantly higher parent reported ADHD symptoms compared to controls, yet only two out of the 18 participants had been diagnosed with ADHD. Conclusion: This study suggests that fine motor skill impairment in children with TS may be more strongly correlated with comorbid ADHD than to TS and tics.

Clarifying the Differences between Patients with Organic Tics and Functional Tic-Like Behaviors.

Due to the global increase in the number of patients with Functional Tic-Like Behaviors (FTLB), it has become increasingly important to find reliable differences between this patient group and patients with organic tics (OTs), which can be used in differential diagnosis. The purpose of this retrospective study was to critically examine both established and suggested differences between the patient groups. A total of 53 FTLB patients and 200 OT patients were included. Several findings from the current literature were replicated in this study: Compared to patients with OTs, patients with FTLB had significantly more complex tics, were older at symptom onset, were more likely to be female, and were less likely to have family members with tics. Furthermore, the study also revealed new differences between the groups: Patients with FTLB had significantly more family members with a psychiatric disorder, were more likely to have experienced an adverse psychosocial event immediately before symptom onset, and had significantly fewer simple tics. Finally, this study was unable to replicate the previously found differences in comorbidities between patients with OTs and FTLB. These findings could contribute significantly to the understanding of FTLB's etiology and to improve diagnosis, as including the presence of simple tics and comorbidities in the diagnostic criteria might be discussed in future studies.

European Society for the Study of Tourette Syndrome 2022 criteria for clinical diagnosis of functional tic-like behaviours: International consensus from experts in tic disorders.

BACKGROUND AND PURPOSE: In 2020, health professionals witnessed a dramatic increase in referrals of young people with rapid onset of severe tic-like behaviours. We assembled a working group to develop criteria for the clinical diagnosis of functional tic-like behaviours (FTLBs) to help neurologists, pediatricians, psychiatrists, and psychologists recognize and diagnose this condition. METHODS: We used a formal consensus development process, using a multiround, web-based Delphi survey. The survey was based on an in-person discussion at the European Society for the Study of Tourette Syndrome (ESSTS) meeting in Lausanne in June 2022. Members of an invited group with extensive clinical experience working with patients with Tourette syndrome and FTLBs discussed potential clinical criteria for diagnosis of FTLBs. An initial set of criteria were developed based on common clinical experiences and review of the literature on FTLBs and revised through iterative discussions, resulting in the survey items for voting. RESULTS: In total, 24 members of the working group were invited to participate in the Delphi process. We propose that there are three major criteria and two minor criteria to support the clinical diagnosis of FTLBs. A clinically definite diagnosis of FTLBs can be confirmed by the presence of all three major criteria. A clinically probable diagnosis of FTLBs can be confirmed by the presence of two major criteria and one minor criterion. CONCLUSIONS: Distinguishing FTLBs from primary tics is important due to the distinct treatment paths required for these two conditions. A limitation of the ESSTS 2022 criteria is that they lack prospective testing of their sensitivity and specificity.

Exposure and Response Prevention: Evaluation of Tic Severity Over Time for Children and Adolescents with Tourette Syndrome and Chronic Tic Disorders.

Tourette syndrome and chronic tic disorders are characterized by the presence of tics. Different behavioral therapies have shown to be efficacious for treating tics in children and adolescents, but Exposure and Response Prevention (ERP) is a less researched method. However, ERP is a method often used in the clinical setting. Therefore, the present study evaluated the severity of tics over time from beginning of ERP to follow-up approximately 1 year after last training session.In total, 116 patients treated with ERP face to face or ERP via web-based videoconferencing were included. The primary outcome measure was tic severity measured with the Danish version of the Yale Global Tic Severity Scale.The results showed that tic severity decreased during ERP and lasted in the follow-up period, with a statistically higher decrease in the group with patients who completed ERP as planned and the group that stopped earlier than planned because of reduction in tics, compared with those who dropped out due to lack of motivation (p < 0.001).The study concludes that ERP seems to have an immediate and a long-term effect on severity of tics, especially in those who complete the program or those who discontinue earlier due to good results.

Increased Number of Functional Tics Seen in Danish Adolescents during the COVID-19 Pandemic.

BACKGROUND: Global increase in functional tics in adolescents has been observed. Differentiating functional from classic tics is important since pathophysiology and treatment differ. We investigated possible triggers for development of functional tics and discuss the possible role of the coronavirus disease 2019 (COVID-19) pandemic and social media exposure in cases of functional tics seen during this period. Moreover, the treatment, and its efficacy is discussed. METHODS: Medical records of 28 Danish adolescents diagnosed with functional tics at the National Tourette Clinic, Department of Pediatrics, Herlev University Hospital, Denmark, from May 2020 to June 2021 have been retrospectively reviewed. Descriptive statistical analyses were used to analyze the data. MAIN FINDINGS: A total of 28 patients diagnosed with functional tics were included, 96.4% girls and 3.6% boys, mean age 14.4 years. Tic phenomenology differed from classic tics with more complex tics and no rostrocaudal progression. Note that 69.2% reported harmful tics. Also, 78.6% had trauma/precipitating event and 40% denounced lockdown related to the COVID-19 pandemic as trigger, both prior to onset of functional tics. Note that 60.7% reported psychiatric symptoms/diagnoses, 42.9% had a first-degree family member with psychiatric symptoms/diagnoses, and 96.4% were exposed to tics on social media prior to onset. Treatment consisted of psychoeducation, elements from cognitive behavioral therapy, and focus on psychiatric symptoms. All patients responded to the treatment. CONCLUSION: The vulnerability of the adolescents is characteristic. Treatment strategy has shown immediate positive effect. Consequences of the COVID-19 pandemic in combination with exposure to tics on social media could be part of the cause for the increase in number of functional tics.

Impact of Tourette Syndrome on Education.

BACKGROUND: Previous studies have shown that Tourette syndrome (TS) has an impact on academic achievements. The aim of this study was to investigate the association between the severity of tics and comorbidities and educational outcomes. METHODS: From 2005 to 2007, 395 participants were included in a large cohort (314 with TS and 81 controls) and the mean age was 12.60 ± 2.64 years. The cohort was re-examined after 4 to 8 years (median 5.6) where n = 276 participants (223 with TS and 53 controls) were included with a mean age of 18.52 ± 2.73 years. At both time points, severity of tics and the presence and severity of psychiatric comorbidity were assessed. Educational achievements were assessed through structured interviews. RESULTS: Children with TS had a lower passing rate at lower secondary and high school compared to healthy controls. More severe vocal tics were associated with fewer passing lower secondary school at a prospective level. At a cross-sectional level, more severe motor tics were associated with fewer passing high school. Tic severity only influenced children with TS without comorbidity. The severity of comorbidity was found to be associated with the educational level at a longitudinal view, but not cross-sectional. CONCLUSION: Overall, children with TS had a lower passing rate at lower secondary school and high school compared to healthy controls. We found that this difference was more likely driven by the severity of comorbidities than tic severity. It is important to be aware of academic achievement in children with TS in order to give them the right support and thereby optimize educational opportunities.

Exposure and Response Prevention for Children and Adolescents with Tourette Syndrome Delivered via Web-Based Videoconference versus Face-to-Face Method.

Chronic tic disorders, such as Tourette syndrome, are characterized by motor and vocal tics. Tics present a considerable burden for some patients, and therefore, effective treatment is important. One evidence-based treatment option is a behavioral therapy called exposure and response prevention (ERP). Despite its effectiveness, access to ERP remains limited due to a lack of treatment sites. Web-based videoconferences can connect patients at home with a therapist located in the hospital, allowing for treatment delivery over a wide geographic area. The primary aim of this study was to compare the development of tics during and 1 year after ERP delivery, respectively, via web-based videoconferences and traditional face-to-face methods in a naturalistic setting. In total, 116 patients treated using either the face-to-face method (n = 72) or web-based videoconferences (n = 44) were included. The primary outcome measure was tic severity. In both training modalities, tic severity decreased during ERP and the effect lasted in the follow-up period. No statistically significant differences in tic severity between the training modalities were found at baseline, last training session, or at follow-up. Our results suggest that ERP delivered via web-based videoconferences is a good alternative to the traditional face-to-face method.

Cytokine profile of pediatric patients with obsessive-compulsive and/or movement disorder symptoms: A review.

Cytokines are an important modulator of the immune system and have been found to be altered significantly in many neurological and psychiatric disorders, like obsessive compulsive disorder (OCD) and movement disorders. Also, in pediatric autoimmune neuropsychiatric disorders associated with group A streptococcal infections (PANDAS), which are characterized by abrupt debut of symptoms of OCD and /or movement disorder symptoms, alterations in the immune system have been suggested. The aim of this paper was to review the current literature on the cytokine profile of pediatric patients with symptoms of OCD and/or movement disorder symptoms. A search of PubMed and Medline was performed with specific keywords to review studies measuring cytokines in pediatric patients with symptoms of OCD and/or movement disorders. Nineteen studies were found, twelve of which included a healthy control group, while four studies had control groups of children with other disorders, primarily neurological or psychiatric. One study compared cytokines measurements to reference intervals, and two studies had a longitudinal design. Many cytokines were found to have significant changes in patients with symptoms of OCD and/or movement disorders compared to both healthy controls and other control groups. Furthermore, differences were found when comparing cytokines in periods of exacerbation with periods of remission of symptoms in study participants. The cytokines that most studies with healthy control groups found to be significantly altered were TNF-α, IL-1ß and IL-17. Although the exact role of these cytokines in OCD and movement disorder symptoms remains unclear, the available literature suggests a proinflammatory cytokine profile. This offers interesting perspectives on the pathogenesis of OCD and/or movement disorder symptoms in children, and further research into the implications of cytokines in neuropsychiatric disorders is warranted.

[Significantly increased incidence of functional tics among children and adolescents].

During 2020, an increase of functional tics in children and adolescents has been observed. In this review, we present phenotypes, differential diagnosis and treatment for functional tics. We discuss potential contributing causes, like the COVID-19 pandemic and the focus on tics on social media. Functional tics are more complex than tics seen in Tourette syndrome and develop more suddenly in relation to stressors mainly in teenage girls. Psychosocial issues and comorbidities must be addressed and treated by a multidisciplinary team through psychoeducation and if necessary, cognitive-behavioural therapy.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part I: assessment.

In 2011 a working group of the European Society for the Study of Tourette Syndrome (ESSTS) has developed the first European assessment guidelines for Tourette syndrome (TS). Now, we present an updated version 2.0 of these European clinical guidelines for Tourette syndrome and other tic disorders, part I: assessment. Therefore, the available literature has been thoroughly screened, supplemented with national guidelines across countries and discussions among ESSTS experts. Diagnostic changes between DSM-IV and DSM-5 classifications were taken into account and new information has been added regarding differential diagnoses, with an emphasis on functional movement disorders in both children and adults. Further, recommendations regarding rating scales to evaluate tics, comorbidities, and neuropsychological status are provided. Finally, results from a recently performed survey among ESSTS members on assessment in TS are described. We acknowledge that the Yale Global Tic Severity Scale (YGTSS) is still the gold standard for assessing tics. Recommendations are provided for scales for the assessment of tics and psychiatric comorbidities in patients with TS not only in routine clinical practice, but also in the context of clinical research. Furthermore, assessments supporting the differential diagnosis process are given as well as tests to analyse cognitive abilities, emotional functions and motor skills.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part III: pharmacological treatment.

In 2011, the European Society for the Study of Tourette Syndrome (ESSTS) published the first European guidelines for Tourette Syndrome (TS). We now present an update of the part on pharmacological treatment, based on a review of new literature with special attention to other evidence-based guidelines, meta-analyses, and randomized double-blinded studies. Moreover, our revision took into consideration results of a recent survey on treatment preferences conducted among ESSTS experts. The first preference should be given to psychoeducation and to behavioral approaches, as it strengthens the patients' self-regulatory control and thus his/her autonomy. Because behavioral approaches are not effective, available, or feasible in all patients, in a substantial number of patients pharmacological treatment is indicated, alone or in combination with behavioral therapy. The largest amount of evidence supports the use of dopamine blocking agents, preferably aripiprazole because of a more favorable profile of adverse events than first- and second-generation antipsychotics. Other agents that can be considered include tiapride, risperidone, and especially in case of co-existing attention deficit hyperactivity disorder (ADHD), clonidine and guanfacine. This view is supported by the results of our survey on medication preference among members of ESSTS, in which aripiprazole was indicated as the drug of first choice both in children and adults. In treatment resistant cases, treatment with agents with either a limited evidence base or risk of extrapyramidal adverse effects might be considered, including pimozide, haloperidol, topiramate, cannabis-based agents, and botulinum toxin injections. Overall, treatment of TS should be individualized, and decisions based on the patient's needs and preferences, presence of co-existing conditions, latest scientific findings as well as on the physician's preferences, experience, and local regulatory requirements.

Concordance and comorbidities among monozygotic twins with tic disorders.

Gilles de la Tourette Syndrome (GTS) is a multifactorial neurodevelopmental disorder characterized by tics and multiple comorbidities. The pathophysiology is not yet fully understood, but both environmental and genetic risk factors seem to be involved. Twin studies provide important knowledge on genetic factors. We assessed the concordance of GTS and chronic tic disorders (CTD) in monozygotic (MZ) twins, and examined tic severity, symptoms of obsessive-compulsive disorder (OCD), attention deficit/hyperactivity disorder and autism spectrum disorder. Twin pairs, where at least one twin was diagnosed with any tic disorder, were identified through Danish Twin Registry, Psychiatric Central Registry, Danish National Patient Registry and National Tourette Clinic, Copenhagen University Hospital, Herlev. Zygosity was tested with single-nucleotide polymorphism (SNP) genotyping and clinical assessment was done with validated tools. 14 MZ twin pairs were included: five were discordant. Seven twin pairs were concordant for GTS, and for two pairs one twin had GTS and the other CTD. Among the twins with CTD or GTS, 50% had at least one comorbidity, which is higher than in background populations. The GTS + OCD-phenotype was significantly more frequent among GTS-concordant than among discordant twins. No statistically significant differences were found between the GTS-concordant and discordant twin pairs regarding tic severity or comorbidities. Thorough clinical assessment and SNP-based genotyping are important when conducting clinical twin studies. We found high concordance of GTS and CTD, which supports the notion that both disorders have common genetic risk factors. Further studies with larger cohorts including dizygotic twins are warranted for more conclusive results.

Clinical guidance for diagnosis and management of suspected Pediatric Acute-onset Neuropsychiatric Syndrome in the Nordic countries.

Pediatric acute-onset neuropsychiatric syndrome is a clinical concept used to describe a subgroup of children with sudden onset of psychiatric and somatic symptoms. The diagnostic term and especially management of children differs depending on the clinical setting to which they present, and the diagnosis and management is controversial. The aim of this paper is to propose a clinical guidance including homogenous diagnostic work-up and management of paediatric acute onset neuropsychiatric syndrome within the Nordic countries. The guidance is authored by a Nordic-UK working group consisting of paediatric neurologist, child psychiatrists and psychologists from Denmark, Norway, Sweden and Great Britain, and is the result of broad consensus. CONCLUSION: Consensus was achieved in the collaboration on work-up and treatment of patients with paediatric acute-onset neuropsychiatric syndrome, which we hope will improve and homogenise patient care and enable future collaborative research in the field.

Association of Group A Streptococcus Exposure and Exacerbations of Chronic Tic Disorders: A Multinational Prospective Cohort Study.

OBJECTIVE: To examine prospectively the association between group A Streptococcus (GAS) pharyngeal exposures and exacerbations of tics in a large multicenter population of youth with chronic tic disorders (CTD) across Europe. METHODS: We followed up 715 children with CTD (age 10.7 ± 2.8 years, 76.8% boys), recruited by 16 specialist clinics from 9 countries, and followed up for 16 months on average. Tic, obsessive-compulsive symptom (OCS), and attention-deficit/hyperactivity disorder (ADHD) severity was assessed during 4-monthly study visits and telephone interviews. GAS exposures were analyzed using 4 possible combinations of measures based on pharyngeal swab and serologic testing. The associations between GAS exposures and tic exacerbations or changes of tic, OC, and ADHD symptom severity were measured, respectively, using multivariate logistic regression plus multiple failure time analyses and mixed effects linear regression. RESULTS: A total of 405 exacerbations occurred in 308 of 715 (43%) participants. The proportion of exacerbations temporally associated with GAS exposure ranged from 5.5% to 12.9%, depending on GAS exposure definition. We did not detect any significant association of any of the 4 GAS exposure definitions with tic exacerbations (odds ratios ranging between 1.006 and 1.235, all p values >0.3). GAS exposures were associated with longitudinal changes of hyperactivity-impulsivity symptom severity ranging from 17% to 21%, depending on GAS exposure definition. CONCLUSIONS: This study does not support GAS exposures as contributing factors for tic exacerbations in children with CTD. Specific workup or active management of GAS infections is unlikely to help modify the course of tics in CTD and is therefore not recommended.

An observational study of emotion regulation in children with Tourette syndrome.

BACKGROUND: Explosive outbursts occur in 25%-70% of children with Tourette syndrome (TS) and may cause more distress than the tics themselves. Previous studies have indicated that a comorbid diagnosis of attention-deficit/hyperactivity disorder (ADHD) is associated with emotional dysregulation in TS; however, this relationship has almost exclusively been studied using parent-reported questionnaires. METHODS: We examined emotion regulation (ER) with an observational measure in 150 medication-naïve children aged 7-12 allocated to four groups: Forty-nine children with TS, 23 children with ADHD, 16 children with TS + ADHD, and 62 typically developing controls. We assessed participants' ER ability, as well as parent-child interactions in the context of a complex puzzle task, and coded the observed behavior with the Tangram Emotion Coding Manual (TEC-M). We examined group differences in ER, as well as associations between ER and severity of symptoms pertaining to TS and ADHD. RESULTS: Children with TS did not differ from controls in their ER ability. However, children with ADHD and TS + ADHD had more problems with ER than those with TS only and controls. Finally, parents of children with ADHD displayed more tension during the experimental task. ER ability was not associated with tic severity nor premonitory urges; however, better ER ability was associated with less severe symptoms of ADHD. CONCLUSIONS: This study is the first to evaluate ER with an observational, clinician-rated measure in a controlled social setting in children with TS. Our findings support earlier questionnaire-based studies by showing impaired ER in children with TS + ADHD, but not in children with TS without comorbidity. These findings inform our understanding of the phenomenology of emotional dysregulation in TS and the role of comorbid disorders.

Reappraisal is an effective emotion regulation strategy in children with Tourette syndrome and ADHD.

BACKGROUND AND OBJECTIVES: Difficulties in emotion regulation (ER) have been associated with several psychiatric disorders, emphasizing a need for a greater understanding of the concept and its associations with disruptive behavior. We aimed to study the ER strategy of cognitive reappraisal with an experimental test to increase our knowledge of emotional processes in child psychopathology. METHODS: In the present study, we examined emotional reactivity and cognitive reappraisal with a computer task in 160 medication-naïve children aged 8-12 comprising four groups: Fifty-eight children with Tourette syndrome (TS), 26 children with attention-deficit/hyperactivity disorder (ADHD), 19 children with TS and ADHD, and 57 typically developing controls. RESULTS: The use of cognitive reappraisal reduced negative affect across all participants and the ability to reappraise was positively correlated with age, whereas reactivity was not. Overall, groups did not differ in reactivity or regulation success. Looking at specific differences within groups, however, only the ADHD group did not significantly decrease negative affect when reappraising. Finally, the use of strategies considered to be efficacious was correlated with regulation success, whereas the use of a less adaptive strategy related to suppression was associated with reactivity, but not regulation of emotions. LIMITATIONS: The study was limited by small, clinical contrast groups and a lack of blinding to diagnostic status in the coding of verbal strategies employed during the task. CONCLUSIONS: Cognitive reappraisal appears to be a beneficial ER strategy for children regardless of diagnostic status. Our findings indicate that children can learn and employ an adaptive ER strategy when instructed in the technique, even in the presence of attention problems, which is highly relevant to therapeutic approaches to dysregulated behavior.

Predictors of the Clinical Course of Tourette Syndrome: A Longitudinal Study.

OBJECTIVE: Tourette syndrome (TS) is a chronic childhood neurodevelopmental disorder characterized by motor and vocal tics and frequent comorbidities. The clinical presentation of Tourette syndrome is heterogeneous and the prognosis for each individual child is difficult to define. This large prospective longitudinal study explores predictors in childhood of the clinical course of tics and comorbidities in early adulthood. METHODS: The cohort was recruited at the Danish National Tourette Clinic. Data were collected at baseline (N = 314; ages, 5-19 years) and follow-up 6 years later (n = 227; ages, 11-26 years) to examine changes in the expression of tics and comorbidities. Childhood clinical factors, represented by 4 binary clinical outcomes, were selected as possible predictors of the clinical course of tics and comorbidities in early adulthood; these were tic severity and diagnoses of obsessive compulsive disorder (OCD), attention-deficit hyperactivity disorder (ADHD), and emotional disorders. RESULTS: The strongest predictors of high tic scores, OCD, or ADHD diagnoses in early adulthood were the corresponding tic (odds ratio [OR]: 1.09), OCD (OR: 1.08), and ADHD (OR: 1.13) severity scores (per scale point) in childhood. Being female (OR: 3.94) and childhood ADHD severity (OR: 1.11) predicted future emotional disorders. Special education, genetic factors, and psychosocial factors were also predictive for the clinical course of Tourette syndrome. CONCLUSION: We identified strong clinical predictors of Tourette syndrome-associated outcomes in early adulthood that are directly applicable to clinical Tourette syndrome populations and may help to guide new patients, plan early interventions, and implement preventive measures.

A superior ability to suppress fast inappropriate responses in children with Tourette syndrome is further improved by prospect of reward.

In children with Tourette syndrome (TS), tics are often attributed to deficient self-control by health-care professionals, parents, and peers. In this behavioural study, we examined response inhibition in TS using a modified Simon task which probes the ability to solve the response conflict between a new non-spatial rule and a highly-overlearned spatial stimulus-response mapping rule. We applied a distributional analysis to the behavioural data, which grouped the trials according to the individual distribution of reaction times in four time bins. Distributional analyses enabled us to probe the children's ability to control fast, impulsive, responses, which corresponded to the trials in the fastest time bin. Additionally, we tested whether the ability to suppress inappropriate action tendencies can be improved further by the prospect of a reward. Forty-one clinically well-characterized medication-naïve children with TS, 20 children with attention-deficit/hyperactivity disorder (ADHD), and 43 typically developing children performed a Simon task during alternating epochs with and without a prospect of reward. We applied repeated measures ANCOVAs to estimate how the prospect of reward modulated reaction times and response accuracy, while taking into account the distribution of the reaction times across trials. We found between-group differences in accuracy when subjects responded relatively fast. The TS group responded more accurately than typically developing control children when resolving the response conflict introduced by the Simon task. The opposite pattern was found in children with ADHD. Prospect of reward improved accuracy rates in all groups. Although the Tourette group performed with superior accuracy in the fast trials, it was still possible for them to benefit from prospect of reward in fast trials. The findings corroborate the notion that children with TS have an enhanced capacity to inhibit fast inappropriate response tendencies. This ability can be improved further by offering a prospect of reward which might be useful during non-pharmacological therapeutic interventions.