Association of small life events with self reports of tic severity in pediatric and adult tic disorder patients: a prospective longitudinal study

Prefrontal allopregnanolone mediates the adverse effects of acute stress in a mouse model of tic pathophysiology

Ample evidence suggests that acute stress can worsen symptom severity in Tourette syndrome (TS); however, the neurobiological underpinnings of this phenomenon remain poorly understood. We previously showed that acute stress exacerbates tic-like and other TS-associated responses via the neurosteroid allopregnanolone (AP) in an animal model of repetitive behavioral pathology. To verify the relevance of this mechanism to tic pathophysiology, here we tested the effects of AP in a mouse model recapitulating the partial depletion of dorsolateral cholinergic interneurons (CINs) seen in post-mortem studies of TS. Mice underwent targeted depletion of striatal CINs during adolescence and were tested in young adulthood. Compared with controls, partially CIN-depleted male mice exhibited several TS-relevant abnormalities, including deficient prepulse inhibition (PPI) and increased grooming stereotypies after a 30-min session of spatial confinement - a mild acute stressor that increases AP levels in the prefrontal cortex (PFC). These effects were not seen in females. Systemic and intra-PFC AP administration dose-dependently worsened grooming stereotypies and PPI deficits in partially CIN-depleted males. Conversely, both AP synthesis inhibition and pharmacological antagonism reduced the effects of stress. These results further suggest that AP in the PFC mediates the adverse effects of stress on the severity of tics and other TS-related manifestations. Future studies will be necessary to confirm these mechanisms in patients and define the circuitry responsible for the effects of AP on tics.

Relationship between adverse childhood experiences and symptom severity in adult men with Tourette Syndrome

Childhood adversity is associated with the development or expression of many neuropsychiatric disorders, including those with strong genetic underpinnings. Despite reported associations between perceived stress and tic severity, the relationship between potentially traumatic events in childhood and Tourette Syndrome (TS), a highly heritable neuropsychiatric disorder, is unknown. This study aimed to assess whether exposure to eight categories of adverse childhood experiences (ACEs) is associated with TS severity and impairment, and whether TS genetic risk modifies this association. Online survey data were collected from 351 adult males with TS who previously participated in genetic studies. Participants completed the ACE questionnaire and a lifetime version of the Yale Global Tic Severity Scale (YGTSS). Demographic and relevant health data were assessed; polygenic risk scores (PRS) measuring aggregated TS genetic risk were derived using genome-wide association data. Univariable and multivariable linear regressions examined the relationships between childhood adversity and retrospectively recalled worst-ever tic severity and impairment, adjusting for covariates. Potential gene-by-environment (GxE) interactions between ACE and PRS were estimated. After covariate adjustment, there was a significant graded dose-response relationship between ACE Scores and increases in lifetime worst-ever tic severity and impairment. There was some evidence that TS genetic risk moderated the relationship between ACE Score and tic impairment, but not tic severity, particularly for individuals with higher TS polygenic risk. We provide evidence that childhood adversity is associated with higher lifetime TS severity and impairment, although future longitudinal studies with genetically-sensitive designs are needed to determine whether these relationships are causal and/or directional.

Increased Risk of Tourette Syndrome with Leukotriene Modifier Use in Children with Allergic Diseases and Asthma: A Nationwide Population-Based Study

(1) Background: Cysteinyl leukotriene receptor antagonists (LTRAs), including montelukast and zafirlukast, are FDA-approved for treating pediatric asthma and allergic diseases. Tourette syndrome (TS), a common neuropsychiatric disorder in children, is associated with allergic diseases and asthma. In this study, we investigated the risk of TS following an LTRA prescription for pediatric allergic diseases. (2) Methods: Children younger than 18 years of age who were newly diagnosed with asthma, allergic rhinitis, or atopic dermatitis between 1 January 2005 and 31 December 2018 and who were registered in the Taiwan National Health Insurance Research Database, which comprises the medical records of nearly 23 million Taiwanese population, were enrolled. LTRA users were matched with randomly selected LTRA non-users by sex, age, asthma-diagnosis year, and urbanization level. In total, 26,984 participants with allergic disease and TS were enrolled and included in the Cox proportional hazards model analysis. (3) Results: Children with allergic disease and asthma treated with LTRAs had a higher risk for TS than LTRA non-users (adjusted hazard ratio 1.376 [95% CI: 1.232−1.536], p < 0.001). LTRA users had a significantly higher risk for TS than LTRA non-users with allergic disease. The cumulative incidence of TS was significantly higher in LTRA users than in non-users with allergic diseases and asthma (log-rank test, p < 0.0001). (4) Conclusion: A prescription of LTRAs, mainly montelukast, increased the risk of TS among children with asthma, allergic rhinitis, or atopic dermatitis. The mechanism underlying the neuropsychiatric effect of LTRAs needs further investigation.

Tics and Emotions

Tics can be associated with neurological disorders and are thought to be the result of dysfunctional basal ganglia pathways. In Tourette Syndrome (TS), excess dopamine in the striatum is thought to excite the thalamo-cortical circuits, producing tics. When external stressors activate the hypothalamic-pituitary-adrenal (HPA) axis, more dopamine is produced, furthering the excitation of tic-producing pathways. Emotional processing structures in the limbic are also activated during tics, providing further evidence of a possible emotional component in motor ticking behaviors. The purpose of this review is to better understand the relationship between emotional states and ticking behavior. We found support for the notion that premonitory sensory phenomena (PSP), sensory stimulation, and other environmental stressors that impact the HPA axis can influence tics through dopaminergic neurotransmission. Dopamine plays a vital role in cognition and motor control and is an important neurotransmitter in the pathophysiology of other disorders such as obsessive–compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD), which tend to be comorbid with ticking disorders and are thought to use similar pathways. It is concluded that there is an emotional component to ticking behaviors. Emotions primarily involving anxiety, tension, stress, and frustration have been associated with exacerbated tics, with PSP contributing to these feelings.

Allopregnanolone: The missing link to explain the effects of stress on tic exacerbation?

The neurosteroid allopregnanolone (3α-hydroxy-5α-pregnan-20-one; AP) elicits pleiotropic effects in the central nervous system, ranging from neuroprotective and anti-inflammatory functions to the regulation of mood and emotional responses. Several lines of research show that the brain rapidly produces AP in response to acute stress to reduce the allostatic load and enhance coping. These effects not only are likely mediated by GABA_A receptor activation but also result from the contributions of other mechanisms, such as the stimulation of membrane progesterone receptors. In keeping with this evidence, AP has been shown to exert rapid, potent antidepressant properties and has been recently approved for the therapy of moderate-to-severe postpartum depression. In addition to depression, emerging evidence points to the potential of AP as a therapy for other neuropsychiatric disorders, including anxiety, seizures, post-traumatic stress disorder and cognitive problems. Although this evidence has spurred interest in further therapeutic applications of AP, some investigations suggest that this neurosteroid may also be associated with adverse events in specific disorders. For example, our group has recently documented that AP increases tic-like manifestations in several animal models of tic disorders; furthermore, our results indicate that inhibiting AP synthesis and signalling reduces the exacerbation of tic severity associated with acute stress. Although the specific mechanisms of these effects remain partially elusive, our findings point to the possibility that the GABAergic activation by AP may also lead to disinhibitory effects, which could interfere with the ability of patients to suppress their tics. Future studies will be necessary to verify whether these mechanisms may apply to other externalising manifestations, such as impulse-control problems and manic symptoms.

Current Understanding of the Genetics of Tourette Syndrome

Gilles de la Tourette syndrome (TS) is a common, childhood-onset psychiatric disorder characterized by persistent motor and vocal tics. It is a heterogeneous disorder in which the phenotypic expression may be affected by environmental factors, such as immune responses. Furthermore, several studies have shown that genetic factors play a vital role in the etiology of TS, as well as its comorbidity with other disorders, including attention deficit hyperactivity disorder, obsessive-compulsive disorder, and autism spectrum disorder. TS has a complex inheritance pattern and, according to various genetic studies, several genes and loci have been correlated with TS. Genome-wide linkage studies have identified Slit and Trk-like 1 (SLITRK1) and histidine decarboxylase (HDC) genes, and candidate gene association studies have extensively investigated the dopamine and serotonin system genes, but there have been no consistent results. Moreover, genome-wide association studies have implicated several genetic loci; however, larger study cohorts are needed to confirm this. Copy number variations, which are polymorphisms in the number of gene copies due to chromosomal deletions or duplications, are considered another significant source of mutations in TS. In the last decade, whole genome/exome sequencing has identified several novel genetic mutations in patients with TS. In conclusion, more studies are needed to reveal the exact mechanisms of underlying TS, which may help to provide more information on the prognosis and therapeutic plans for TS.

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

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

Cholinergic Stress Signals Accompany MicroRNA-Associated Stereotypic Behavior and Glutamatergic Neuromodulation in the Prefrontal Cortex

Stereotypic behavior (SB) is common in emotional stress-involved psychiatric disorders and is often attributed to glutamatergic impairments, but the underlying molecular mechanisms are unknown. Given the neuro-modulatory role of acetylcholine, we sought behavioral-transcriptomic links in SB using TgR transgenic mice with impaired cholinergic transmission due to over-expression of the stress-inducible soluble 'readthrough' acetylcholinesterase-R splice variant AChE-R. TgR mice showed impaired organization of behavior, performance errors in a serial maze test, escape-like locomotion, intensified reaction to pilocarpine and reduced rearing in unfamiliar situations. Small-RNA sequencing revealed 36 differentially expressed (DE) microRNAs in TgR mice hippocampi, 8 of which target more than 5 cholinergic transcripts. Moreover, compared to FVB/N mice, TgR prefrontal cortices displayed individually variable changes in over 400 DE mRNA transcripts, primarily acetylcholine and glutamate-related. Furthermore, TgR brains presented c-fos over-expression in motor behavior-regulating brain regions and immune-labeled AChE-R excess in the basal ganglia, limbic brain nuclei and the brain stem, indicating a link with the observed behavioral phenotypes. Our findings demonstrate association of stress-induced SB to previously unknown microRNA-mediated perturbations of cholinergic/glutamatergic networks and underscore new therapeutic strategies for correcting stereotypic behaviors.

Targeting Cognitions, Emotions, and Behaviors in a Complex Case of Tourette Syndrome: Illustration of a Psychophysiological Perspective

Recent research stresses that cognitive and affective processes are implicated in Tourette Syndrome (TS) and might influence treatment. The cognitive-behavioral and psychophysiological (CoPs) approach posits that negative appraisals and maladaptive action-planning elicit negative emotions and behaviors that increase muscular tension and thus the urge to tic in TS. Hence, the CoPs targets cognitive-behavioral and affective processes increasing tension prior to tic onset. This article provides clinically novel information in the implementation and utility of the CoPs approach in a severe case of a young man with TS and a range of comorbidities marked by negative cognitions and emotions as well as planning deficits with a long-term follow-up. He received 14 sessions of CoPs therapy. Tic severity significantly decreased post-treatment with maintenance up to 36-months. The process measure of action-planning improved significantly from pre-treatment to 12-months follow-up. Results support the feasibility and acceptability of the CoPs in treating complex TS cases.

Tics and Tourette Syndrome

PURPOSE OF REVIEW

The purpose of this article is to present current information on the phenomenology, epidemiology, comorbidities, and pathophysiology of tic disorders and discuss therapy options. It is hoped that a greater understanding of each of these components will provide clinicians with the necessary information to deliver thoughtful and optimal care to affected individuals.

RECENT FINDINGS

Recent advances include the finding that Tourette syndrome is likely due to a combination of several different genes, both low-effect and larger-effect variants, plus environmental factors. Pathophysiologically, increasing evidence supports involvement of the cortical-basal ganglia-thalamocortical circuit; however, the primary location and neurotransmitter remain controversial. Behavioral therapy is first-line treatment, and pharmacotherapy is based on tic severity. Several newer therapeutic agents are under investigation (eg, valbenazine, deutetrabenazine, cannabinoids), and deep brain stimulation is a promising therapy.

SUMMARY

Tics, defined as sudden, rapid, recurrent, nonrhythmic motor movements or vocalizations, are essential components of Tourette syndrome. Although some tics may be mild, others can cause significant psychosocial, physical, and functional difficulties that affect daily activities. In addition to tics, most affected individuals have coexisting neuropsychological difficulties (attention deficit hyperactivity disorder, obsessive-compulsive disorder, anxiety, mood disorder, disruptive behaviors, schizotypal traits, suicidal behavior, personality disorder, antisocial activities, and sleep disorders) that can further impact social and academic activities or employment.

The psychology of Tourette disorder: Revisiting the past and moving toward a cognitively-oriented future

Tourette syndrome is a neurodevelopmental disorder characterized by chronic tics (i.e., repetitive and stereotyped movements and vocalizations) and premonitory urges (i.e., aversive sensations preceding tics that are alleviated once a tic is performed). Research supports that dysfunctional neurobiological and psychological processes interact and contribute to the development and maintenance of tics. However, psychological theories of Tourette syndrome and accompanying research have mainly focused on the emotional states (e.g., anxiety and frustration) and behavioural principles (i.e., operant conditioning) that play a role in tic exacerbation. This selective review summarizes key discoveries pertaining to the emotional and behavioural aspects of Tourette syndrome but also proposes a more comprehensive, cognitively-oriented conceptualization of the disorder. Specifically, it is proposed that maladaptive beliefs about discomfort and about one's ability to cope with discomfort underlie negative appraisals of unpleasant sensory experiences in individuals with Tourette syndrome. It is further suggested that these beliefs lead individuals to perceive premonitory urges in a catastrophic manner and thereby enhance tic frequency. Concrete research avenues to empirically examine these hypotheses are outlined and clinical implications for the field of cognitive-behaviour therapy are discussed.

Major and minor life events, personality and psychopathology in children with tourette syndrome

Environmental, psychological, and biological interactions underlie many psychopathologies. Tourette's Syndrome (TS) has an obvious biological substrate but environmental factors and personality play substantial roles in its expression. We aimed to study the interrelationships between stressful life events, personality traits, tics, and comorbid disorders in children with TS. To this end, 132 children with TS and 49 healthy controls were recruited for the study. Major life events in the 12-months prior to testing and minor life events in the month prior to testing were retrospectively assessed using the Life Experiences Survey (LES) and the Brief Adolescent Life Events Scale (BALES), respectively. Personality was assessed with the Junior Temperament and Character Inventory (JTCI). Tics, obsessive compulsive symptoms, attention deficit and hyperactivity symptoms, anxiety, depression and aggression were assessed by self-report questionnaires and semi-structured interviews. We found that major life events correlated with the severity of tics expression and complexity, and comorbid psychopathology. Minor life events correlated with more severe symptomatology. High levels of harm avoidance were related to more obsessions, anxiety, and depression whereas high levels of self-directedness were protective. To conclude, TS expression in childhood should be understood as the result of an interaction between biological, personality and environmental factors.

What makes you tic? Translational approaches to study the role of stress and contextual triggers in Tourette syndrome

Tourette syndrome (TS) is a neurodevelopmental condition characterized by multiple, recurring motor and phonic tics. Rich empirical evidence shows that the severity of tics and associated manifestations is increased by several stressors and contextual triggers; however, the neurobiological mechanisms responsible for symptom exacerbation in TS remain poorly understood. This conceptual gap partially reflects the high phenotypic variability in tics, as well as the existing difficulties in operationalizing and standardizing stress and its effects in a clinical setting. Animal models of TS may be highly informative tools to overcome some of these limitations; these experimental preparations have already provided critical insights on key aspects of TS pathophysiology, and may prove useful to identify the neurochemical alterations induced by different stressful contingencies. In particular, emerging knowledge on the role of contextual triggers in animal models of TS may inform the development of novel pharmacological interventions to reduce tic fluctuations in this disorder.

Tic Frequency Decreases during Short-term Psychosocial Stress - An Experimental Study on Children with Tic Disorders

It has been suggested that psychosocial stress influences situational fluctuations of tic frequency. However, evidence from experimental studies is lacking. The current study investigated the effects of the Trier Social Stress Test (TSST-C) on tic frequency in 31 children and adolescents with tic disorders. A relaxation and a concentration situation served as control conditions. Patients were asked either to suppress their tics or to "tic freely." Physiological measures of stress were measured throughout the experiment. The TSST-C elicited a clear stress response with elevated levels of saliva cortisol, increased heart rate, and a larger number of skin conductance responses. During relaxation and concentration, the instruction to suppress tics reduced the number of tics, whereas during stress, the number of tics was low, regardless of the given instruction. Our study suggests that the stress might result in a situational decrease of tic frequency.

Annual research review: The neurobehavioral development of multiple memory systems--implications for childhood and adolescent psychiatric disorders

Extensive evidence indicates that mammalian memory is organized into multiple brains systems, including a 'cognitive' memory system that depends on the hippocampus and a stimulus-response 'habit' memory system that depends on the dorsolateral striatum. Dorsal striatal-dependent habit memory may in part influence the development and expression of some human psychopathologies, particularly those characterized by strong habit-like behavioral features. The present review considers this hypothesis as it pertains to psychopathologies that typically emerge during childhood and adolescence. These disorders include Tourette syndrome, attention-deficit/hyperactivity disorder, obsessive-compulsive disorder, eating disorders, and autism spectrum disorders. Human and nonhuman animal research shows that the typical development of memory systems comprises the early maturation of striatal-dependent habit memory and the relatively late maturation of hippocampal-dependent cognitive memory. We speculate that the differing rates of development of these memory systems may in part contribute to the early emergence of habit-like symptoms in childhood and adolescence. In addition, abnormalities in hippocampal and striatal brain regions have been observed consistently in youth with these disorders, suggesting that the aberrant development of memory systems may also contribute to the emergence of habit-like symptoms as core pathological features of these illnesses. Considering these disorders within the context of multiple memory systems may help elucidate the pathogenesis of habit-like symptoms in childhood and adolescence, and lead to novel treatments that lessen the habit-like behavioral features of these disorders.

The Modulating Role of Stress in the Onset and Course of Tourette’s Syndrome

Accumulating data indicate a common occurrence of tic exacerbations and periods of psychosocial stress. Patients with Tourette’s syndrome (TS) also exhibit aberrant markers of hypothalamic-pituitary-adrenal (HPA) axis activation. Based on these findings, a functional relationship between stress and tic disorders has been suggested, but the underlying mechanism of how stress may affect tic pathology remains to be elucidated. We suggest that dopaminergic and noradrenergic neurotransmission as well as immunology play a crucial role in mediating this relationship. Two possibilities of causal direction might be assumed: (a) psychosocial stress might lead to an exacerbation of tics via activation of HPA axis and subsequent changes in neurotransmission or immunology and (b) TS-related abnormalities in neurotransmission or immunology result in a higher vulnerability of affected patients to respond to psychosocial stress with a strong activation of the HPA axis. It may also be the case that both assumptions hold true and interact with each other.

Life events and Tourette syndrome

INTRODUCTION

Tourette syndrome (TS) is a neuropsychiatric developmental disorder characterized by the presence of multiple motor tics and one or more vocal tics. Although TS is primarily biological in origin, stress-diatheses interactions most probably play a role in the course of the illness. The precise influence of the environment on this basically biological disorder is difficult to ascertain, particularly when TS is complicated by comorbidities. Among the many questions that remain unresolved are the differential impact of positive and negative events and specific subtypes of events, and the importance of major crucial events relative to minor daily ones to tic severity.

OBJECTIVES

To examine the relationships between life events, tic severity and comorbid disorders in Tourette Syndrome (TS), including OCD, ADHD, anxiety, depression and rage attacks. Life events were classified by quantity, quality (positive or negative) and classification types of events (family, friends etc.).

SUBJECTS

Sixty patients aged 7-17 years with Tourette syndrome or a chronic tic disorder were recruited from Psychological Medicine Clinic in Schneider Children's Medical Center of Israel.

INSTRUMENTS

Yale Global Tic Severity Scale; Children's Yale Brown Obsessive Compulsive Scale; Life Experiences Survey; Brief Adolescent Life Events Scale; Screen for Child Anxiety Related Emotional Disorders; Child Depression Inventory/Beck Depression Inventory; ADHD Rating Scale IV; Overt Aggression Scale.

RESULTS

Regarding tics and minor life events, there was a weak but significant correlation between severity of motor tics and the quantity of negative events. No significant correlation was found between tic severity and quantity of positive events. Analysis of the BALES categories yielded a significant direct correlation between severity of vocal tics and quantity of negative events involving friends. Regarding comorbidities and minor life events, highly significant correlations were found with depression and anxiety. Regarding tics and major life events, significant correlation was found between the quantity of major life events and the severity of motor tics, but not vocal tics. Regarding comorbidities and major life events, significant correlation was found between the severity of compulsions, ADHD, and aggression and the subjects' personal evaluation of the effect of negative major life events on their lives.

CONCLUSIONS

Minor life events appear to be correlated with tic severity and comorbidities in children and adolescents with Tourette syndrome. The lack of an association between major life events and tic severity further emphasizes the salient impact of minor life events that occur in temporal proximity to the assessment of tic severity. Clinically, the results match our impression from patient narratives wherein they "blamed" the exacerbations in tics on social interactions. The high correlation between negative life events and depression, anxiety and compulsions symptoms, were reported also in previous studies. In conclusion, These findings may have clinical implications for planning supportive psychotherapy or cognitive behavioral therapy for this patient population.

Neuroendocrine aspects of Tourette syndrome

There is sparse evidence suggesting the participation of neuroendocrine mechanisms, mainly involving sex and stress steroid hormones, to the pathophysiology of neurodevelopmental disorders such as Tourette syndrome (TS) and obsessive-compulsive disorder (OCD). Patients with TS exhibit a sex-specific variability in gender distribution (male/female ratio=3-4/1) and in its natural history, with a severity peak in the period around puberty. The administration of exogenous androgens may worsen tics in males with TS, whereas drugs counteracting the action of testosterone might show some antitic efficacy. This suggests a higher susceptibility of patients with TS to androgen steroids. There are insufficient data on the regulation of the hypothalamic-pituitary-gonadal (HPG) axis in TS. However, preliminary evidence suggests that a subgroup of women with TS might be more sensitive to the premenstrual trough of estrogen levels. Patients with TS exhibit differences in a number of behavioral, cognitive, and anatomical traits that appear to be sex related. There is a body of evidence supporting, albeit indirectly, the hypothesis of an increased exposure to androgenic steroids during the very early phases of neural development. Animal models in rodents suggest a complex role of gonadal hormones upon the modulation of anxiety-related and stereotyped behaviors during adult life. Patients with TS exhibit an enhanced reactivity of the hypothalamic-pituitary-adrenal axis to external stressors, despite a preserved diurnal cortisol rhythm and a normal restoration of the baseline activity of the axis following the acute stress response. Preliminary evidence suggests the possible implication of oxytocin (OT) in disorders related to the TS spectrum, especially non-tic-related OCD. The injection of OT in the amygdala of rodents was shown to be able to induce hypergrooming, suggesting the possible involvement of this neuropeptide in the pathophysiology of complex, stereotyped behaviors. In contrast, there is anecdotal clinical evidence that tics improve following periods of affectionate touch and sexual intercourse.

Tourette syndrome and other tic disorders in childhood, adolescence and adulthood

BACKGROUND

Tourette syndrome is a combined motor and vocal tic disorder that begins in childhood and takes a chronic course. It arises in about 1% of all children, with highly varying severity. Transient and usually mild tics are seen in as many as 15% of all children in elementary school. The diagnosis is often delayed by several years.

METHODS

We selectively reviewed the pertinent literature, including the guidelines of the European Society for the Study of Tourette Syndrome for the diagnosis and treatment of tic disorders.

RESULTS

Tic disorders usually take a benign course, with spontaneous improvement in adolescence in about 90% of patients. Psychoeducation is the basis of treatment in each case and almost always brings marked emotional relief. Specific treatment is needed only for more severe tics and those that cause evident psychosocial impairment. 80-90% of patients with Tourette syndrome have comorbidities (attention deficit-hyperactivity disorder, obsessive-compulsive disorder, depression, anxiety, emotional dysregulation, autoaggression), which often impair their quality of life more than the tics do and therefore become the main target of treatment. There is little evidence for the efficacy of treatment for tics. Small-scale controlled studies with a brief follow-up period have been carried out for some neuroleptic drugs. Behavior therapy should be tried before drug treatment. A further option for very severely affected adults is deep brain stimulation.

CONCLUSION

Because of the low level of the available evidence, no definitive recommendations can be made for the treatment of tics.

New treatments for tic disorders

Tics vary in severity from infrequent and barely noticeable to nearly continuous and highly disruptive. Treatment of tic disorders depends on the severity of the tics, the distress they cause, and the effects they have on school, work, or daily activities. Many tics do not interfere with school or everyday life and do not require specific treatment. Comorbid disorders such as attention deficit hyperactivity disorder, anxiety, and obsessive-compulsive disorder occur in more than 50% of patients. The associated comorbidity can be more bothersome than the tics themselves. Treatment should be aimed at the most troubling symptom. Education and reassurance are often sufficient for mild and occasional tics. For tics of moderate severity, clonidine and guanfacine have a reasonable safety profile. They are considered as first-line medications. With clonidine, start with 0.05 mg at bedtime. Increase as needed and as tolerated by 0.05 mg every 4 to 7 days to a maximum dosage of 0.3 to 0.4 mg/day divided three or four times a day. With guanfacine, start with 0.5 mg at bedtime. The dosage may be increased as needed and as tolerated by 0.5 mg every week to a maximum dosage of 3 to 4 mg/day, divided twice a day. There are emerging data that behavioral therapy is effective for treatment of tics in some individuals. Dopamine receptor blockers are the most potent medications for treating severe tics. The efficacy appears to be proportionate to the affinity for dopamine D2 receptors. Thus, standard antipsychotic medications such as haloperidol, pimozide, or fluphenazine are the most potent. However, these medications commonly cause bothersome side effects. Therefore, we recommend use of atypical neuroleptics before standard neuroleptics in most patients. Risperidone is usually the first choice and may have efficacy for behavior problems that often accompany tics. Start with 0.01 mg/kg/dose once a day; dosage may be increased by 0.02 mg/kg/day at weekly intervals, up to 0.06 mg/kg/dose once a day. Ziprasidone and olanzapine are reasonable alternatives.

Tourette syndrome and other tic disorders

Tic disorders, including Tourette syndrome, are an intriguing group of paroxysmal movement abnormalities that begin in childhood, have a fluctuating course, are capable of causing psychosocial and physical problems, and often improve by early adulthood. These disorders are frequently associated with a variety of comorbid problems whose negative effects may exceed those of tics. Therapy is strictly symptomatic and usually includes educational, behavioral, and a variety of pharmacological therapies. Although there is strong evidence supporting an inherited basis, the precise genetic abnormality remains unknown. A proposed poststreptococcal autoimmune etiology remains controversial. Pathophysiologically, tics appear to arise from an alteration within cortico-striatal-thalamo-cortical circuits, but the definitive site is unknown. Evidence supports an abnormality of synaptic neurotransmission, likely involving the dopaminergic system.

The impact of a stress induction task on tic frequencies in youth with Tourette Syndrome

Tourette Syndrome (TS) is a neuropsychiatric disorder characterized by motor and vocal tics. Tic fluctuations are common and thought to be attributable in part, to contextual variables. Stress is one such variable, but its effects and mechanism of action are poorly understood. The current study measured the effects of a stress induction task on tic frequencies during periods of suppression and non-suppression of tics. Ten youth with TS between the ages of 9 and 17 were exposed to four conditions in random sequence: free-to-tic baseline (BL), reinforced tic suppression (SUP), reinforced tic suppression plus a stress induction task (SUP + STRESS), and a stress induction task alone (STRESS). Tic frequencies did not differ during STRESS and BL. Tic frequencies were greater in SUP + STRESS than SUP. Stress may impact tics through disrupting suppression efforts. Clinically, results suggest that interventions designed to improve tic inhibition in the presence of acute stressors may be beneficial.

Methylphenidate and comorbid anxiety disorder in children with both chronic multiple tic disorder and ADHD

OBJECTIVE

To determine if comorbid anxiety disorder is associated with differential response to immediate release methylphenidate (MPH-IR) in children with both ADHD and chronic multiple tic disorder (CMTD).

METHOD

Children with (n = 17) and without (n = 37) diagnosed anxiety disorder (ANX) were evaluated in an 8-week, placebo-controlled trial with rating scales and laboratory measures.

RESULTS

The +ANX group obtained more severe parent, teacher, and child ratings of anxiety and more severe parent ratings of depression, tics, oppositional defiant disorder (ODD), and peer aggression than the -ANX group. Treatment with short-term MPH-IR was associated with improvement in ADHD, ODD, and peer aggression in the +ANX group. When controlling for ODD severity, there were no apparent group differences in therapeutic response to MPH-IR in children ±ANX. There was little evidence that MPH-IR contributed to improvement in anxiety or depression symptoms in the +ANX group. There was some indication that children with comorbid anxiety may differentially experience greater increase in systolic blood pressure (0.5 mg/kg of MPH-IR > placebo).

CONCLUSION

Findings suggest that the co-occurrence of diagnosed CMTD+ADHD+ANX represents a particularly troublesome clinical phenotype, at least in the home setting. Comorbid anxiety disorder was not associated with a less favorable response to MPH-IR in children with ADHD+CMTD, but replication with larger samples is warranted before firm conclusions can be drawn about potential group differences.

Tourette syndrome in children: an updated review

Tourette syndrome (TS) is a common neuropsychiatric disorder in children characterized by multiple motor and vocal tics that fluctuate in severity and lasting for at least 1 year. Boys are more commonly affected than girls. Symptoms usually begin with simple motor or vocal tics which then evolve into more complex motor and vocal tics over time. Premonitory sensory urges are common in children over the age of 8 years, and these urges help distinguish tics from symptoms of other movement disorders. Common comorbidities of TS include attention deficit hyperactivity disorder, obsessive-compulsive disorder and learning difficulties. Several genes have been assessed as candidate genes for TS; environmental factors such as stress and streptococcal infections might also contribute to its etiology. The pathophysiology of TS mainly involves dysfunction of basal ganglia-related circuits and hyperactive dopaminergic innervations. A thorough history assessment and neurological examination are important for the correct diagnosis and differentiation from other movement disorders. Treatment for TS should focus on improving the patient's social functioning, minimizing the impairment from cormobid disorders, and controlling tics, if they are severe. Commonly used medications for TS include a2-adrenergic agonists and atypical neuroleptics. Habit reversal therapy is an effective option for TS, and repetitive transcranial magnetic stimulation may be a promising approach for severe cases.

The neurobiology of repetitive behavior: …and men

In young, typically developing children, repetitive behavior similar to that in certain neuropsychiatric syndromes is common. Whereas this behavior is adaptive in typical development, in many disorders it forms a core component of symptoms and causes prominent impairment in the daily life of affected individuals. Understanding the neurobiological mechanisms involved repetitive behavior will improve our understanding of the pathogenesis of developmental neuropsychiatric disorders, stimulating novel approaches to these conditions. However, studies on the neurobiology of human repetitive behavior have often been limited to distinct conditions and generalization has been hindered by inconsistent terminology. In this paper, we synthesize the 'disorder-driven' literature, building on findings from fundamental animal research and translational models. These findings suggest a model for classifying repetitive behavior by its neuroanatomical correlates.

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.

Immunopathogenic mechanisms in tourette syndrome: A critical review

Tourette syndrome (TS) has a multifactorial etiology, in which genetic, environmental, immunological and hormonal factors interact to establish vulnerability. This review: (i) summarizes research exploring the exposure of TS patients to immune-activating environmental factors, and (ii) focuses on recent findings supporting a role of the innate and adaptive immune systems in the pathogenesis of TS and related disorders. A higher exposure prior to disease onset to group A beta-haemolytic streptococcal (GABHS) infections in children with tics and obsessive-compulsive (OC) symptoms has been documented, although their influence upon the course of disease remains uncertain. Increased activation of immune responses in TS is suggested by changes in gene expression profiles of peripheral immune cells, relative frequency of lymphocyte subpopulations, and synthesis of immune effector molecules. Increased activity of cell-mediated mechanisms is suggested by the increased expression of genes controlling natural killer and cytotoxic T cells, increased plasma levels of some pro-inflammatory cytokines which correlate with disease severity, and increased synthesis of antineuronal antibodies. Important methodological differences might account for some inconsistency among results of studies addressing autoantibodies in TS. Finally, a general predisposition to autoimmune responses in TS patients is indicated by the reduced frequency of regulatory T cells, which induce tolerance towards self-antigens. Although the pathogenic role of immune activation in TS has not been definitively proven, a pathophysiological model is proposed to explain the possible effect of immunity upon dopamine transmission regulation and the generation of tics.

Comparative study of children with ADHD only, autism spectrum disorder + ADHD, and chronic multiple tic disorder + ADHD

OBJECTIVE

Identification of differences among children with ADHD only, autism spectrum disorder (ASD)+ADHD, and chronic multiple tic disorder (CMTD)+ADHD may lead to better understanding of clinical phenotypes.

METHOD

Children were evaluated using the parent- and teacher-completed questionnaires.

RESULTS

All three groups were highly similar in severity of oppositional defiant disorder and conduct disorder symptoms; however, the ASD+ADHD group generally exhibited the most severe anxiety, although the CMTD+ADHD group had the most severe generalized anxiety. The two comorbid groups had the most involved medical histories and the greatest likelihood of a family history of psychopathology.

CONCLUSION

Groups differed in clinically meaningful ways, and the apparent association between tics and anxiety may explain in part the elevated levels of anxiety in both comorbid groups. Collectively, results suggest that ADHD may be better conceptualized as a family of interrelated syndromes defined in part by comorbid conditions and that continued research is clearly warranted.

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.

The influence of contextual factors on tic expression in Tourette's syndrome: a review

Symptoms of Tourette's syndrome vary in frequency and intensity. Although such variability may be the result of deficits in the underlying neurological system, tic expression can also be systematically impacted by contextual factors. This article reviews research on the impact of several contextual factors on tic expression and discusses implications for future research and treatment development.

The development of stimulus control over tics: a potential explanation for contextually-based variability in the symptoms of Tourette syndrome

Research has demonstrated that providing reinforcement for tic-free intervals can decrease tic frequency in controlled analogue settings. The aim of the current study was to determine whether reinforcement could be used to create stimulus control over tic expression. Ten children with chronic tic disorders (including Tourette syndrome) completed four discrimination training sessions. Each session consisted of three exposures to each of three, 5 min. conditions presented in a random order. In one condition, participants were reinforced for tic absence on a 10-s fixed interval schedule in the presence of a purple light. In a second condition, participants were instructed to suppress their tics, but were not reinforced for doing so in the presence of an orange light. In a third condition, participants were instructed not to suppress their tics in the presence of two non-illuminated lights. Confirming findings from other studies, results showed that reinforcing tic suppression reduced tic frequency to a greater extent than only providing instructions to suppress. To test for stimulus control, a fifth session was conducted following the aforementioned discrimination training sessions. The fifth session consisted of three exposures to each of three 5 min. conditions presented in a random order. In one condition, a purple light was illuminated. In a second condition, an orange light was illuminated. In a third condition, neither light was illuminated. Across all three conditions, instructions to suppress (or not suppress) tics were not provided, and reinforcers for successful suppression were not delivered. Results indicated that in the presence of the purple light, tics were significantly lower than when neither light was illuminated. These findings provide preliminary support for the idea that a history of differential reinforcement in various contexts may play a role explaining variability in tic symptom expression.

Is onset of Tourette syndrome influenced by life events?

The aim of this study is to investigate the possible relationship between stressful life events, personality, and onset of Tourette syndrome in children. The study group included 93 subjects aged 7-18 years: 41 with Tourette syndrome (TS), 28 with obsessive-compulsive disorder (OCD), and 24 healthy controls. Diagnoses were based on the Child Schedule for Schizophrenia and Affective Disorders (K-SADS). All children were tested with the Screen for Child Anxiety Related Emotional Disorders, Children's Yale Brown Obsessive Compulsive Scale, Beck Depression Inventory or Children's Depression Inventory, the Life Experience Survey, and the Junior Temperament and Character Inventory. The findings were compared among the groups. Subjects with Tourette syndrome and healthy controls had significantly less stressful life events than subjects with (OCD). There were no significant differences between the TS subjects and the healthy controls. This finding applied to total lifetime events, total lifetime negative events, and events in the year before and after illness onset. Subjects with TS and the healthy controls also showed a significantly lesser impact of life events than subjects with OCD. The Tourette syndrome group showed a significantly lesser impact of stressful life events than controls. Harm avoidance tended to be higher in the patients with Tourette syndrome and comorbid attention deficit hyperactivity disorder and obsessive-compulsive disorder than in patients with Tourette syndrome only. There seemed to be no association between life events, diagnosis, and personality. Although there is some research suggesting that tics can be influenced by the environment, the onset of Tourette syndrome does not seem to be related to stressful life events, nor to an interaction between stressful life events and personality.

Psychosocial stress predicts future symptom severities in children and adolescents with Tourette syndrome and/or obsessive-compulsive disorder

BACKGROUND

The goals of this prospective longitudinal study were to monitor levels of psychosocial stress in children and adolescents with Tourette syndrome (TS) and/or obsessive-compulsive disorder (OCD) compared to healthy control subjects and to examine the relationship between measures of psychosocial stress and fluctuations in tic, obsessive-compulsive (OC), and depressive symptom severity.

METHODS

Consecutive ratings of tic, OC and depressive symptom severity were obtained for 45 cases and 41 matched healthy control subjects over a two-year period. Measures of psychosocial stress included youth self-report, parental report, and clinician ratings of long-term contextual threat. Structural equation modeling for unbalanced repeated measures was used to assess the temporal sequence of psychosocial stress with the severity of tic, OC and depressive symptoms.

RESULTS

Subjects with TS and OCD experienced significantly more psychosocial stress than did the controls. Estimates of psychosocial stress were predictive of future depressive symptoms. Current levels of psychosocial stress were also a significant predictor of future OC symptom severity, but not vice versa. Current OC symptom severity was a predictor of future depressive symptom severity, but not vice versa. Current levels of psychosocial stress and depression were independent predictors of future tic severity, even after controlling for the effect of advancing chronological age.

CONCLUSIONS

The impact of antecedent psychosocial adversity is greater on future depressive symptoms than for tic and/or OC symptoms. Worsening OC symptoms are also a predictor of future depressive symptoms. Advancing chronological age is robustly associated with reductions in tic severity.

Reactivity of Tic Observation Procedures to Situation and Setting

Tic frequency was assessed and compared across home and clinic as well as three experimentally-manipulated situations in order to assess the phenomenon of tic reactivity. Forty-three youngsters with chronic tic disorder recruited from two geographically-distinct sites were videotaped over three weekly laboratory visits under each of the following conditions: (1) alone/camera present, (2) other present/camera present, and (3) alone/camera hidden. Contrary to expectation, more tics were observed during overt as compared to covert observation, while the presence of another person had no overall impact on tic expression. Mean tic counts obtained from clinic observation did not significantly differ from those obtained at home collected either one day before or after. Tic frequency counts were remarkably stable over the three weekly assessments both at home and clinic. Study findings are consistent with past observations that tic expression can be influenced by environmental factors and suggest the stability of tic frequency may exhibit greater temporal and setting stability than previously thought. The clinical and research implications of these results are discussed.

Tourette syndrome: the self under siege

Tourette syndrome is a neurodevelopmental disorder characterized by motor and vocal tics--rapid, repetitive, stereotyped movements or vocalizations. Tourette syndrome typically has a prepubertal onset, and boys are more commonly affected than girls. Symptoms usually begin with transient bouts of simple motor tics. By age 10 years, most children are aware of nearly irresistible somatosensory urges that precede the tics. These urges likely reflect a defect in sensorimotor gating because they intrude into the child's conscious awareness and become a source of distraction and distress. A momentary sense of relief typically follows the completion of a tic. Over the course of hours, tics occur in bouts, with a regular intertic interval. Tics increase during periods of emotional excitement and fatigue. Tics can become "complex" in nature and appear to be purposeful. Tics can be willfully suppressed for brief intervals and can be evoked by the mere mention of them. Tics typically diminish during periods of goal-directed behavior, especially those that involve both heightened attention and fine motor or vocal control, as occur in musical and athletic performances. Over the course of months, tics wax and wane. New tics appear, often in response to new sources of somatosensory irritation, such as the appearance of a persistent vocal tic (a cough) following a cold. Over the course of years, tic severity typically peaks between 8 and 12 years of age. By the end of the second decade of life, many individuals are virtually tic free. Less than 20% of cases continue to experience clinically impairing tics as adults. Tics rarely occur in isolation, and other coexisting conditions--such as behavioral disinhibition, hypersensitivity to a broad range of sensory stimuli, problems with visual motor integration, procedural learning difficulties, attention-deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder, depression, anxiety, and emotional instability--are often a greater source of impairment than the tics themselves. Emerging behavioral treatments of Tourette syndrome are based in part on an understanding of the moment-to-moment experience of somatosensory urges and motor response. With identification of specific genes of major effect and advances in our understanding of the neural circuitry of sensorimotor gating, habit formation, and procedural memory--together with insights from postmortem brain studies, in vivo brain imaging, and electrophysiologic recordings--we might be on the threshold of a deeper understanding of the phenomenology and natural history of Tourette syndrome.

Association of common cold with exacerbations in pediatric but not adult patients with tic disorder: a prospective longitudinal study

Cross-sectional data and case studies suggest a temporal relationship between fluctuations in tic severity and preceding infections. In this study, we aimed to examine this possible relationship in a prospective longitudinal design. Two groups of tic disorder patients were included, a pediatric group between 7 and 15 years of age (n = 20), and an adult group over 15 years of age (n = 41). During a 24-week period, participants were asked to fill out weekly self questionnaires regarding the presence of tic exacerbations and the experience of the common cold. In addition, 6 throat swabs were taken at monthly intervals and cultured for streptococci; also, 3 serial serum assessments of streptococcal antibodies were performed at 8-week intervals. In the pediatric group, our results indicated a strong association between the self report of a common cold and a symptom exacerbation 4 weeks later (Odds ratio = 4.685; p = 0.001). In the adult group, we found no association between reports of common cold and tic exacerbations. Association with streptococcal infections could not be determined owing to the limited number of observed streptococcal infections. Thus, this study points to a hitherto unknown association of common viral infections with tic exacerbations in children, which may support the involvement of immune dysregulation in tic disorders.