Quetiapine treatment of children and adolescents with Tourette's disorder

Pharmacological treatment of Tourette's syndrome: from the past to the future

Tourette's syndrome (TS) is a neuropsychiatric disease featuring tics and vocal tics, with a prevalence of approximately 1%, including 75% of the total number of male patients. TS seriously disturbs the patients' career, education, and life and brings a serious and unbearable psychological burden to the patients themselves and their families. At present, there are no specific clinical medications recommended for treating TS. Therefore, it is necessary to select the appropriate medication for symptomatic treatment based on the doctor's personal experience and the patient's symptoms, with the main goal of relieving symptoms, thus improving the patient's social skills and psychological problems. Here we conducted a comprehensive search on PubMed to review and organize the history and current status of the development of drug therapy for TS through a timeline format. We also systematically evaluated the effects of each drug for TS treatment to summarize the current problems and new research directions and to provide some ideas for clinical treatment.

Research encouraging off-label use of quetiapine: A systematic meta-epidemiological analysis

BACKGROUND

Researchers often conduct small studies on testing a drug's efficacy in off-label indications. If positive results from these exploratory studies are not followed up by larger, randomized, double-blinded trials, physicians cannot be sure of a drug's clinical value. This may lead to off-label prescriptions of ineffective treatments. We aim to describe the way clinical studies fostered off-label prescription of the antipsychotic drug quetiapine (Seroquel).

METHODS

In this systematic meta-epidemiological analysis, we searched EMBASE, MEDLINE, Cochrane CENTRAL and PsycINFO databases and included clinical studies testing quetiapine for unapproved indications between May 1995 and May 2022. We then assessed the frequency with which publications providing low-level evidence suggesting efficacy of quetiapine for off-label indications was not followed up by large, randomized and double-blinded trials within 5 years.

RESULTS

In total, 176 published studies were identified that reported potential efficacy of quetiapine in at least 26 indications. Between 2000 and 2007, publication of exploratory studies suggesting promise for off-label indications rapidly outpaced publication of confirmatory trials. In the 24 indications with a minimum of 5 years of follow-up from the first positive exploratory study, 19 (79%) were not followed up with large confirmatory trials within 5 years. At least nine clinical practice guidelines recommend the use of quetiapine for seven off-label indications in which published confirmatory evidence is lacking.

CONCLUSION

Many small, post-approval studies suggested the promise of quetiapine for numerous off-label indications. These findings generally went unconfirmed in large, blinded, randomized trials years after first being published. The imbalance of exploratory and confirmatory studies likely encourages ineffective off-label treatment.

Clinical Practice Patterns in Tic Disorders Among Movement Disorder Society Members

Background

Tic disorders belong to the broad spectrum of pediatric and adult movement disorders. The wide variability in clinical presentations, applied assessment tools, and treatments are poorly understood.

Objectives

To map practices and knowledge base of movement disorder clinicians concerning clinical features, pathophysiology, and treatment approaches in tic disorders.

Methods

A 33-item survey was developed by the Tic Disorders and Tourette syndrome Study Group members of the Movement Disorder Society. The survey was distributed to the complete society membership and included responses from 346 members, 314 of whom reported treating tic disorders.

Results

Approximately one third of survey respondents (35%) frequently evaluated patients with tics. The data revealed widespread use of existing guidelines (about 70%) and screening for comorbid disorders (>90%). The most common investigations used to rule out secondary causes of tics were imaging (92%), laboratory tests (66%) and neurophysiology (38%). Functional tics were the second most common tic etiology following primary tics. Only 27% of respondents reported confidence in knowledge about tic pathogenesis. Top rated interventions to treat tics were psychoeducation, cognitive behavioral intervention for tics (CBIT) and treatment for neuropsychiatric comorbidities. Antipsychotics were ranked as the most effective pharmacologic tic intervention.

Conclusions

The majority of movement disorders specialists do not frequently encounter tics. There was sparse knowledge about tic pathophysiology. Psychoeducation, CBIT, the treatment of neuropsychiatric comorbidities and use of antipsychotics emerged as the most common interventions to treat tics. These results provide insight into what will be needed to improve the diagnosis and treatment of tic disorders.

Drug and Non-drug Treatment of Tourette Syndrome

Background:

Tourette Syndrome (TS) is a neurodevelopmental disorder characterized by multiple repetitive motor and vocal tics. In most patients, its clinical course has a waxing and waning nature and most patients, usually children, will benefit from tolerant environmental and psychoeducation. Patients with more complicated tics, in particular, those with significant comorbidities will require drug therapy.

Objective:

The present paper is a mini-review of the current therapeutic arsenal for TS with reference to drug and non-drug management approach.

Methods:

A systematic survey of medical literature regarding the treatment decision making and the reported clinical trials or accumulating experience with different medications or other therapeutic modalities which were proven beneficial over the years.

Results:

Reviewing the literature indicates that dopamine antagonists, such as haloperidol and pimozoide, are the most reliable agents in terms of treatment response. Due to numerous adverse effects, newer atypical anti-psychotic drugs have been shown effective. Other widely accepted medications include alpha-2 adrenergic agonists, benzamides, dopamine depleting agents, benzodiazepines and dopamine depleting agents. In more selective and intractable cases botulinum toxin, dopamine agonists and cannabinoids should be also considered. Non-pharmacologic therapies reported beneficial effects, which include on the one hand, non-invasive behavioral techniques, such as comprehensive behavior therapy for tics. While on the other hand, in cases with particular protracted pharmaco-resistant tics electric stimulation techniques, such as deep brain stimulation, have been shown to be successful.

Conclusion:

Currently, there are numerous multifarious options for treatment of tics and other comorbid symptoms of TS. Nevertheless, treatment options and decision-making algorithms are still a clinical challenge.

Area Covered:

A step by step decision-making and various drugs and non-pharmacologic modalities appropriate for the management of TS.

Update on the Pharmacological Treatment of Tics with Dopamine-Modulating Agents

More than 40 years of research and clinical practice have proven the effectiveness of dopamine receptor antagonists in the pharmacological treatment of tics. A blockade of the striatal dopamine-D2 receptors is mainly responsible for their tic-reducing effect. A broad spectrum of dopamine-modulating agents, such as typical and atypical antipsychotics, but also dopamine receptor agonists are used with an immanent discord between experts about which of them should be considered as first choice. The present Review outlines the state of the art on pharmacological treatment of tics with dopamine-modulating agents by giving an systematic overview of studies on their effectiveness and a critical discussion of their specific adverse effects. It is considered as an update of a previous review of our research group published in 2013. The Review closes with a description of the current resulting treatment recommendations including the results of a first published revised survey on European expert's prescription preferences. Based on the enormously growing evidence on its effectiveness and safety, aripiprazole currently seems to be the most promising agent in the pharmacological treatment of tics. Furthermore, benzamides (especially tiapride), which are commonly used in Europe, have proven their excellent effectiveness-tolerability profile over decades in clinical practice and are therefore also highly recommended for the treatment of tics. Nevertheless, pharmacological treatment of tics remains an indiviual choice depending on each patient's own specific needs.

Current Approaches and New Developments in the Pharmacological Management of Tourette Syndrome

Tourette syndrome (TS) is a neurodevelopmental disorder of unknown etiology characterized by spontaneous, involuntary movements and vocalizations called tics. Once thought to be rare, TS affects 0.3-1% of the population. Tics can cause physical discomfort, emotional distress, social difficulties, and can interfere with education and desired activities. The pharmacologic treatment of TS is particularly challenging, as currently the genetics, neurophysiology, and neuropathology of this disorder are still largely unknown. However, clinical experience gained from treating TS has helped us better understand its pathogenesis and, as a result, derive treatment options. The strongest data exist for the antipsychotic agents, both typical and atypical, although their use is often limited in children and adolescents due to their side-effect profiles. There are agents in a variety of other pharmacologic categories that have evidence for the treatment of TS and whose side-effect profiles are more tolerable than the antipsychotics; these include clonidine, guanfacine, baclofen, topiramate, botulinum toxin A, tetrabenazine, and deutetrabenazine. A number of new agents are being developed and tested as potential treatments for TS. These include valbenazine, delta-9-tetrahydrocannabidiol, and ecopipam. Additionally, there are agents with insufficient data for efficacy, as well as agents that have been shown to be ineffective. Those without sufficient data for efficacy include clonazepam, ningdong granule, 5-ling granule, omega-3 fatty acids, and n-acetylcysteine. The agents that have been shown to be ineffective include pramipexole and metoclopramide. We will review all of the established pharmacologic treatments, and discuss those presently in development.

Treatment-refractory Tourette Syndrome

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

Activating and Tranquilizing Effects of First-Time Treatment with Aripiprazole, Olanzapine, Quetiapine, and Risperidone in Youth

OBJECTIVE

To assess activating and tranquilizing effects of second-generation antipsychotics (SGAs) in youth.

METHODS

As part of the naturalistic inception cohort study, "Second-generation Antipsychotic Treatment Indication, Effectiveness and Tolerability in Youth (SATIETY)," subjective ratings of activating and tranquilizing symptoms were obtained monthly for 3 months from antipsychotic-naïve youth initiating SGAs using the Treatment Emergent Symptoms Scale (TESS). Discontinuation rates, and TESS-reported symptom rates, and severity were related to clinical and treatment parameters. Two compound measures of TESS were defined: presence of any daytime activating (ACTIVATION+) and sedating symptoms (SEDATION+).

RESULTS

In 327 antipsychotic-naïve youth originally initiating the four studied SGAs, discontinuation due to sedation was marginally highest with quetiapine (13.0%) followed by olanzapine (7.3%), risperidone (4.2%), and aripiprazole (2.0%) (p = 0.056). Two hundred fifty-seven antipsychotic-naïve youth (13.8 ± 3.6 years, male = 57.8%) initiated aripiprazole (n = 40), olanzapine (n = 45), quetiapine (n = 36), or risperidone (n = 135) and completed ≥1 postbaseline follow-up visit. Baseline prevalence of ACTIVATION+ (39.9%) or SEDATION+ (54.1%) did not differ between SGAs. Rates of both compound measures changed significantly over time (decrease for ACTIVATION+, p = 0.0002; increase for SEDATION+, p < 0.0001) with slight differences between SGAs, explained by lower rates of ACTIVATION+ with olanzapine (p = 0.002) and slightly higher rates of ACTIVATION+ with aripiprazole (p = 0.018) during follow-up, and lower rates of SEDATION+ with aripiprazole (p = 0.018). All four SGAs reduced insomnia (p = 0.001) and increased hypersomnia (p < 0.001). Postbaseline prevalence of drowsiness, the most frequent, but mild TESS complaint was 85%, without SGA differences. Younger age was associated with activating symptoms, higher age with sedating symptoms, and lower baseline functioning increased both. Psychomotor retardation rates were high in subjects with schizophrenia-spectrum disorders, whereas stimulant comedication was associated with psychomotor activation, regardless of diagnosis.

CONCLUSIONS

Although small SGA-specific differences in activating/sedating compound side effect measures were noted, independent predictors of single TESS ratings included clinical parameters, rather than specific SGAs, suggesting a need for carefully individualized treatment strategies.

The role of atypical antipsychotics for treatment of Tourette's syndrome: an overview

Tourette's syndrome (TS) is a neuropsychiatric disorder of childhood onset characterized by multiple motor and phonic tics that fluctuate over time. Tic symptoms often improve by late adolescence, but some children and adults with TS may experience significant tic-related morbidity, including social and family problems, academic difficulties, and pain. When more conservative interventions are not successful, and when certain psychiatric co-morbidities further complicate the clinical profile, treating TS with an atypical antipsychotic medication may be a reasonable second-tier approach. However, the evidence supporting efficacy and safety of the atypical antipsychotics for treatment of tics is still very limited. The objective of this paper is to provide an updated overview of the role of atypical antipsychotics for treatment of TS, with evidence-based guidance on their use. Evidence for efficacy of different typical and atypical antipsychotics for treatment of tics was examined by conducting a systematic, keyword-related search of 'atypical antipsychotics' and 'Tourette's syndrome' in PubMed (National Library of Medicine, Washington, DC, USA). Four recent treatment consensus publications were also reviewed. This review focused on literature published from 2000 to 2013 and on available randomized controlled trials in TS. Evidence supporting the use of atypical antipsychotics for treatment of TS is limited. There are few randomized medication treatment trials in TS (i.e. risperidone, aripiprazole, ziprasidone), which employed varying methodologies, thereby restricting meaningful comparisons among studies. Future collaborations among clinical sites with TS expertise employing high-quality study design may better elucidate the role of atypical antipsychotics for treatment of TS.

Use of quetiapine in children and adolescents

The atypical antipsychotic quetiapine has been used in different psychotic and non-psychotic disorders in children and adolescents in randomized clinical trials, open-label studies and chart reviews. Most of these studies suggest that quetiapine may be a promising agent with a potential for use in young patients. The aim of this paper is to critically review available literature on quetiapine in the treatment of children and adolescents with a variety of psychiatric disorders, including psychotic disorders, bipolar disorders (manic and depressive episodes), conduct disorder, autism spectrum disorder, Tourette's syndrome and personality disorders. Furthermore, we report on possible neurochemical pathways involved during treatment with quetiapine, and discuss some issues that are clinically relevant in daily practice, such as titration strategies, safety and tolerability, and monitoring possible side effects. Controlled studies support the short-term efficacy for treating psychosis, mania, and aggression within certain diagnostic categories. However, although quetiapine seems well tolerated in various pediatric populations during acute and intermediate treatments, and hyper-prolactinemia and extra-pyramidal side effects are consistently low among studies, weight gain and alterations in lipid profile need to be closely monitored. Furthermore, the distal benefit/risk ratio during long-term treatment remains to be determined.

Updates in medical and surgical therapies for Tourette syndrome

Tourette syndrome is a complex neurobehavioral disorder defined by multiple motor and at least 1 vocal tic, persisting over 1 year, waxing and waning in severity, and not explained by another condition. The condition may range from mild nuisance to debilitating and disabling in severity. Management includes counseling and reassurance, behavioral interventions, pharmacologic, and rarely, surgical interventions. Traditionally, alpha-2 agonists and dopamine receptor antagonists have been utilized. In addition, a number of different pharmacotherapies have been implemented in the search for improved management of tics with better tolerability. In rare, severely disabling cases, neuromodulation with deep brain stimulation may be indicated. Optimal brain targets and candidate selection are still in evolution. This article will review the evidence for current medical and surgical therapies with a focus on recent updates.

Clinical effectiveness of aripiprazole in short-term treatment of tic disorder in children and adolescents: a naturalistic study

BACKGROUND/PURPOSE

The purpose of this study was to evaluate the effectiveness and tolerability of aripiprazole in short-term treatment of children and adolescents with tic disorder (TD).

METHODS

This was a 14-week, prospective, open-label flexible dose trial of aripiprazole. We enrolled patients with TD aged between 4 years and 18 years. They received aripiprazole (dose: 2.5 mg/day) initially, which was then adjusted according to clinical response. The severity was assessed by the Yale Global Tic Severity Score (YGTSS) at 0, 2, 6, 10, and 14 weeks. The linear mixed models were used for evaluation of the YGTSSs at each follow-up, which were compared with baseline scores.

RESULTS

Eighty-one patients were enrolled in this study. Nine patients withdrew from the study with complaints of adverse side effects. Of the remaining 72 patients, 15 patients discontinued medications prematurely due to being free of symptoms for over 2 weeks. Two patients discontinued medications due to no significant improvement. The mean scores had significantly decreased since the 2nd week (p < 0.01). The mean reduction was 51.0% in the motor tic scores, 67.1% in the vocal tic scores, and 70.0% in the total YGTSSs. The common adverse effects were sedation (32.1%) and increased appetite (22.2%). A slight increase in average body weight was noted, from 32.7 to 33.7 kg (+1.0 kg, p < 0.05).

CONCLUSION

Aripiprazole is effective for short-term treatment of TD, especially vocal tics, in children and adolescents with mild adverse effects. However, further double-blind trials against placebo or other medications are needed to verify the efficacy of aripiprazole in the pharmacotherapy of TD.

Clinical pharmacology of dopamine-modulating agents in Tourette's syndrome

Forty years of research and clinical practice have proved dopamine (DA) receptor antagonists to be effective agents in the treatment of Tourette's syndrome (TS), allowing a significant tic reduction of about 70%. Their main effect seems to be mediated by the blockade of the striatal DA-D2 receptors. Various typical and atypical agents are available and there is still discord between experts about which of them should be considered as first choice. In addition, there are suggestions to use DA receptor agonists such as pergolide or non-DA-modulating agents. The present chapter is focusing on the clinical pharmacology of DA-modulating agents in the treatment of TS. The introduction outlines their clinical relevance and touches on the hypotheses of the role of DA in the pathophysiology of TS. Subsequently, general information about the mechanisms of action and adverse effects are provided. The central part of the chapter forms a systematic review of all DA-modulating agents used in the treatment of TS, including an overview of studies on their effectiveness, and a critical discussion of their specific adverse effects. The present chapter closes with a summary of the body of evidence and a description of the resulting recommendations for the pharmacological treatment of TS.

Therapie der Tic-Störungen

Seit dem Erscheinen unserer letzten Übersichtsarbeit zur «Therapie der Tic-Störungen» in der Zeitschrift für Kinder- und Jugendpsychiatrie wurden große Fortschritte auf diesem Gebiet erzielt. So wurden einzelne Bausteine auf dem Weg zur optimalen Behandlung konkretisiert, z. B. Veröffentlichung einheitlicher Kriterien zur Behandlungsindikation oder Entwicklung und Evaluierung eines detaillierten verhaltenstherapeutischen Manuals zum Habit-Reversal-Training. Daneben sind neue Therapiemöglichkeiten, wie das Medikament Aripiprazol oder die Tiefenhirnstimulation, erfolgreich implementiert worden. Auch wurde das Augenmerk viel stärker auf begleitende Störungen, wie ADHS und Zwangsstörungen, gerichtet, da diese in der Regel eine besonders starke Beeinträchtigung für die weitere Entwicklung des Kindes oder Jugendlichen darstellen. Dennoch bestehen weiterhin große Wissenslücken über die Effektivität der einzelnen Behandlungsmethoden, möglicher Kombinationsbehandlungen sowie deren direkter Vergleich untereinander. Daneben erschwert das Fehlen jeglicher Parameter zur Vorhersage der individuell sehr unterschiedlichen Entwicklung der Tics über die nächsten Monate und Jahre eine evidenzbasierte Therapieempfehlung und damit das Erlernen der Feinheiten bei der Behandlung von Tic-Störungen. Zusammengefasst ist noch immer eine große klinische Erfahrung für die Therapieentscheidungen beim einzelnen Patienten von großem Vorteil angesichts der enormen Bandbreite an individueller Tic-Symptomatik und Komorbidität gepaart mit den unvorhersehbaren Schwankungen im zeitlichen Verlauf.

Pharmacological treatment of tic disorders and Tourette Syndrome

The present review gives an overview of current pharmacological treatment options of tic disorders and Tourette Syndrome (TS). After a short summary on phenomenology, clinical course and comorbid conditions we review indications for pharmacological treatment in detail. Unfortunately, standardized and large enough drug trials in TS patients fulfilling evidence based medicine standards are still scarce. Treatment decisions are often guided by individual needs and personal experience of treating clinicians. The present recommendations for pharmacological tic treatment are therefore based on both scientific evidence and expert opinion. As first-line treatment of tics risperidone (best evidence level for atypical antipsychotics) or tiapride (largest clinical experience in Europe and low rate of adverse reactions) are recommended. Aripiprazole (still limited but promising data with low risk for adverse reactions) and pimozide (best evidence of the typical antipsychotics) are agents of second choice. In TS patients with comorbid attention deficit hyperactivity disorder (ADHD) atomoxetine, stimulants or clonidine should be considered, or, if tics are severe, a combination of stimulants and risperidone. When mild to moderate tics are associated with obsessive-compulsive symptoms, depression or anxiety sulpiride monotherapy can be helpful. In more severe cases the combination of risperidone and a selective serotonin reuptake inhibitor should be given. In summary, further studies, particularly randomized, double-blind, placebo-controlled trials including larger and/or more homogenous patient groups over longer periods are urgently needed to enhance the scientific basis for drug treatment in tic disorders. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.

Canadian guidelines for the evidence-based treatment of tic disorders: pharmacotherapy

This article seeks to provide the practising clinician with guidance on the pharmacological management of tic disorders in children and adults. We performed a systematic review of the literature on the treatment of tic disorders. A multi-institutional group of 14 experts in psychiatry, child psychiatry, neurology, pediatrics, and psychology engaged in a consensus meeting. The evidence was presented and discussed, and nominal group techniques were employed to arrive at consensus on recommendations. A strong recommendation is made when the benefits of treatment clearly outweigh the risks and burdens, and can apply to most patients in most circumstances without reservation. With a weak recommendation, the benefits, risks, and burdens are more closely balanced, and the best action may differ depending on the circumstances. Based on these principles, weak recommendations were made for the use of pimozide, haloperidol, fluphenazine, metoclopramide (children only), risperidone, aripiprazole, olanzapine, quetiapine, ziprasidone, topiramate, baclofen (children only), botulinum toxin injections, tetrabenazine, and cannabinoids (adults only). Strong recommendations were made for the use of clonidine and guanfacine (children only). While the evidence supports the efficacy of many of the antipsychotics for the treatment of tics, the high rates of side effects associated with these medications resulted in only weak recommendations for these drugs. In situations where tics are not severe or disabling, the use of a medication with only a weak recommendation is not warranted. However, when tics are more distressing and interfering, the need for tic suppression to improve quality of life is stronger, and patients and clinicians may be more willing to accept the risks of pharmacotherapy.

Update on the role of antipsychotics in the treatment of Tourette syndrome

Tourette syndrome (TS) is a neuropsychiatric disorder with typical onset in childhood and characterized by chronic occurrence of motor and vocal tics. The disorder can lead to serious impairments of both quality of life and psychosocial functioning, particularly for those individuals displaying complex tics. In such patients, drug treatment is recommended. The pathophysiology of TS is thought to involve a dysfunction of basal ganglia-related circuits and hyperactive dopaminergic innervations. Congruently, dopamine receptor antagonism of neuroleptics appears to be the most efficacious approach for pharmacological intervention. To assess the efficacy of the different neuroleptics available, a systematic, keyword-related search in PubMed (National Library of Medicine, Washington, DC) was undertaken. Much information on the use of antipsychotics in the treatment of TS is based on older data. Our objective was to give an update and therefore we focused on papers published in the last decade (between 2001 and 2011). Accordingly, the present review aims to summarize the current and evidence-based knowledge on the risk-benefit ratio of both first and second generation neuroleptics in TS.

Treatment of tics and tourette syndrome

OPINION STATEMENT

Tics come in a variety of types and frequencies; have a waxing and waning course; are exacerbated by stress, anxiety, and fatigue; and often resolve or improve in the teenage or early adult years. Tourette syndrome requires the presence of chronic, fluctuating motor and phonic tics. In addition to tics, individuals with Tourette syndrome often have a variety of comorbid conditions such as attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder, depression and anxiety, episodic outbursts, and academic difficulties. These conditions often are a greater source of difficulty than the tics themselves. All patients with tics should be evaluated to assure proper diagnosis and to identify any associated psychopathology or academic difficulty. The treatment of tics begins with education of the patient and family, including discussions about the fundamentals of tics: their characteristics, etiology, outcomes, and available treatments. Therapy should be individualized based on the extent of impairment, available support, ability to cope, and the presence of other problems. Indications for the treatment of tics include psychosocial problems (loss of self-esteem, comments from peers, excessive worries about tics, diminished participation in activities), functional difficulties, classroom disruption, and physical discomfort. A variety of behavioral approaches can be used. Recent studies have emphasized the value of comprehensive behavioral intervention for tics (CBIT). Because habit reversal is the major component of CBIT, a cooperative patient, the presence of a premonitory urge, and a committed family are essential ingredients for success. If tic-suppressing medication is required, a two-tier approach and monotherapy are recommended. First-tier medications, notably the α-adrenergic agonists, are recommended for individuals with milder tics, especially persons with both tics and ADHD. Second-tier medications include various typical and atypical neuroleptics. Their sequence of prescription is often based on physician experience; I favor pimozide and fluphenazine. Atypical antipsychotics, such as risperidone and aripiprazole, have some advantages based on their side-effect profile and are particularly beneficial in individuals with significant co-existing behavioral issues. As will become readily apparent, however, few medications have been adequately assessed. Deep brain stimulation is an emerging therapy, but further data are required to optimize the location of electrode placement and stimulation and to determine precise indications for its implementation. Stimulant medication is effective in treating ADHD in children with tics; studies reducing concerns about its use are discussed.

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.

European clinical guidelines for Tourette syndrome and other tic disorders. Part II: pharmacological treatment

To develop a European guideline on pharmacologic treatment of Tourette syndrome (TS) the available literature was thoroughly screened and extensively discussed by a working group of the European Society for the Study of Tourette syndrome (ESSTS). Although there are many more studies on pharmacotherapy of TS than on behavioral treatment options, only a limited number of studies meets rigorous quality criteria. Therefore, we have devised a two-stage approach. First, we present the highest level of evidence by reporting the findings of existing Cochrane reviews in this field. Subsequently, we provide the first comprehensive overview of all reports on pharmacological treatment options for TS through a MEDLINE, PubMed, and EMBASE search for all studies that document the effect of pharmacological treatment of TS and other tic disorders between 1970 and November 2010. We present a summary of the current consensus on pharmacological treatment options for TS in Europe to guide the clinician in daily practice. This summary is, however, rather a status quo of a clinically helpful but merely low evidence guideline, mainly driven by expert experience and opinion, since rigorous experimental studies are scarce.

Treatment strategies for tics in Tourette syndrome

TOURETTE SYNDROME (TS) IS A CHRONIC NEURODEVELOPMENTAL DISORDER CHARACTERIZED BY TICS: repetitive, involuntary movements and vocalizations. These symptoms can have a significant impact on patients' daily functioning across many domains. Tics tend to be most severe in child and adolescent sufferers, so their presence has the potential to impact a period of life that is both critical for learning and is often associated with the experience of greater social tension and self-consciousness than adulthood. Furthermore, control over tics that lead to physical impairment or self-injurious behaviour is of vital importance in maintaining health and quality of life. There are numerous complicating factors in the prescription of treatment for tics, due to both the side effects associated with alleviating agents and patient characteristics, such as age and comorbid conditions. This review summarizes literature pertaining to the efficacy and safety of both traditionally prescribed and more modern medications. We also discuss the merits of behavioural and surgical techniques and highlight newer emerging treatments. Although treatment response is to some extent variable, there are a number of agents that are clearly useful as first-line treatments for TS. Other interventions may be of most benefit to patients exhibiting refractory tics or more specific symptom profiles.

Evidence-based pharmacotherapy for pediatric obsessive-compulsive disorder and chronic tic disorders

In recent years, much progress has been made in pharmacotherapy for pediatric obsessive-compulsive disorder (OCD) and chronic tic disorders (CTDs). What were previously considered relatively intractable conditions now have an array of efficacious medicinal (and psychosocial) interventions available at clinicians’ disposal, including selective serotonin reuptake inhibitors, atypical antipsychotics, and alpha-2 agonists. The purpose of this review is to discuss the evidence base for pharmacotherapy with pediatric OCD and CTDs with regard to efficacy, tolerability, and safety, and to put this evidence in the context of clinical management in integrated behavioral healthcare. While there is no single panacea for these disorders, there are a variety of medications that provide considerable relief for children with these disabling conditions.

Open-label study comparing the efficacy and tolerability of aripiprazole and haloperidol in the treatment of pediatric tic disorders

Due to its unique pharmacodynamic properties of dopamine partial agonist activity, and its association with few and mild side effects, aripiprazole is a candidate atypical antipsychotic for patients with tic disorders. This open-label study compared the efficacy and tolerability of aripiprazole with haloperidol, a typical antipsychotic widely used to treat patients with tic disorders. Forty-eight children and adolescents with tic disorders were recruited from the outpatient clinic at South Korea and treated with aripiprazole (initial dose, 5.0 mg/d; maximum dose 20 mg/d) or haloperidol (initial dose, 0.75 mg/d; maximum dose, 4.5 mg/d) for 8 weeks. Treatment efficacy was measured using the yale global tic severity scale (YGTSS), and tolerability was measured using the extrapyramidal symptom rating scale (ESRS) and an adverse effects checklist. Total tic scores as measured by the YGTSS decreased over time in both groups (p < 0.001) without any significant differences between groups. ESRS scores were significantly higher in the haloperidol group during the 4 weeks after commencement of medication (p < 0.05). These results indicate that aripiprazole may be a promising drug in the treatment of children and adolescents with tic disorders. Further controlled studies are needed to determine the efficacy and tolerability of aripiprazole in these patients.

[Aripiprazole - a medical treatment alternative for Tourette Syndrome in childhood and adolescence]

OBJECTIVE

We report a case-series of seven patients with a medical history of at least two years of tic disorder treated with the partial dopamine agonist aripiprazole to illustrate its efficacy as a treatment alternative for motor and vocal tics in children and adolescents.

METHOD

A case series of five patients with Tourette Syndrome (TS) and two with chronic motor tic disorder (age range 8; 7-18; 1 year), the majority of whom had been refractory to treatment with other neuroleptics or had ceased treatment due to intolerable side effects, were treated for eight weeks with aripiprazole. Before and after treatment, parents rated the severity of motor and vocal tic symptoms on the Yale Tourette Syndrome Checklist.

RESULTS

Within eight weeks mean motor tic symptoms decreased by 66% and mean vocal tic symptoms decreased by 26%. Mean effective dosage was 14.3 mg/day (min. 5 mg, max. 30 mg). Symptoms of comorbid ADHD or Obsessive Compulsive Disorder were not significantly influenced. During medication only mild side effects were observed, e.g., abdominal pain, fatigue and increased emotional sensitivity. No patient dropped out of treatment due to side effects.

CONCLUSIONS

Aripiprazole may be an effective pharmacologic treatment alternative for individuals with chronic motor tic disorder and TS. It induces quick, significant and sustained effects with few generally mild and transient side effects, if anything. Its effectiveness, especially relative to comorbidities, should be verified in double-blind, placebo-controlled studies.

Tic suppression: the medical model

Tics are intermittent, repetitive, patterned but usually nonrhythmic motor movements or sounds performed in response to urges or involuntarily. They are the cardinal symptom required for a DSM-IV-TR diagnosis of Tourette's disorder (TD). Many children with TD present with mild tics that cause no significant impairment. However, when tics cause pain or interference, medical treatment is reasonable. This article reviews current evidence for treatment of tics in TD with medications as well as deep brain stimulation and transcranial magnetic stimulation. It concludes with some context for understanding this literature, relevant to treatment decisions and future treatment research in TD.

[Algorithms for the medical treatment of Attention-Deficit/Hyperactivity Disorder with specific co-morbidities]

BACKGROUND

In clinical practice Attention Deficit Hyperactivity Disorder (ADHD) is a challenge for diagnostic and therapeutic effort due to a number of co-morbidities, e.g., depression, anxiety disorders, Tourette Syndrome and impulsive aggression that can be a complication or a result of the core symptoms or evolve parallel to the basic disorder. The therapeutic strategies incorporate a multimodal access with a combination of psychosocial, psychotherapeutic and medical measures. The combination of various medical substances for an effective treatment of these co-morbidities, especially Serotonin-Reuptake Inhibitors (SSRIs) and atypical neuroleptics with psychostimulants has substantially reduced the occurrence of the main symptoms of the disorder in many cases and thus can also lead to a decrease in the occurrence of co-morbidities. Where this strategy fails to suffice, it is recommended to consider medical treatment strategies in combination with other substances that alternatively or in combination with psychostimulants increasingly positively influence co-morbid symptoms.

OBJECTIVE AND METHOD

Based on a Medline literature search we report the results of combined medical approaches for an effective medical treatment of the ADHD core symptoms accompanied by serious co-morbid symptoms. Hereby we focused on the above cited disorders. Combined treatment options that include psychostimulants are considered in particular. Moreover, recommendations for medical treatment strategies oriented to the clinical cardinal symptoms are presented in the form of algorithms. Evidence-based literature and practical experience are critically reviewed.

RESULTS

In most cases it will be sufficient to begin the treatment with a psychostimulant because co-morbid symptoms also will be significantly reduced. However, if the latter are in the foreground of the clinical picture, antidepressants or neuroleptics are to be considered as primary or equivalent treatment options.

CONCLUSIONS

Since in Germany most of the substances discussed are not licensed for use in paediatric treatment, proofs of efficacy in children are lacking. One also must reckon with the frequent occurrence of side effects. Finally, little data exist on treatments that include the use of psychostimulants.

Emerging treatments for Tourette's disorder

Tourette's disorder is a childhood-onset neuropsychiatric disorder characterized by multiple motor and vocal tics. Many children with Tourette's disorder improve throughout adolescence. However, some adults with Tourette's disorder still experience severe symptoms and significant disability. This article examines the evidence base for current treatments for Tourette's disorder. Emerging treatments such as deep brain stimulation, habit reversal therapy, and repetitive trans-cranial magnetic stimulation are also discussed.

Aripiprazole treatment of children and adolescents with Tourette disorder or chronic tic disorder

OBJECTIVE

This study was conducted to evaluate the effectiveness of aripiprazole to reduce the severity and frequency of tic symptoms and to evaluate the additional effects of aripiprazole on weight changes in children and adolescents with Tourette disorder (TD) or chronic tic disorders.

METHODS

A 12-week, open-label trial with flexible dosing strategy of aripiprazole was performed with 15 participants, aged 7-19 years. The Yale Global Tic Severity Scale was applied and the baseline, week 3, 5, 9, and end point scores were compared. The mean body mass index (BMI) at baseline and end point were also compared.

RESULTS

Significant decreases in the scores of motor and phonic tics, global impairment, and global severity were demonstrated between baseline and week 3, and the scores continued to improve thereafter. No difference was observed between the baseline and end point BMI.

CONCLUSION

This study demonstrates that a relatively low dose of aripiprazole can be used to control tic symptoms effectively in children and adolescents with TD and chronic tic disorders without causing significant weight gain. Additional double-blind studies are needed to establish the definitive efficacy of aripiprazole in treating children and adolescents with chronic tic symptoms.

Clinical effectiveness of quetiapine in children and adolescents with Tourette's syndrome : a retrospective case-note survey

BACKGROUND AND OBJECTIVE

Tourette's syndrome is a relatively common biological genetic disorder with a broad spectrum of neurobehavioural manifestations. Unfortunately, treatment of the condition is often unsatisfactory and all available drugs are associated with potential adverse effects. We therefore aimed to investigate the efficacy of quetiapine, a newer atypical antipsychotic, in the treatment of children and adolescents with Tourette's syndrome.

METHODS

This was a retrospective study carried out in outpatient clinics. Twelve patients aged 8-18 years with Tourette's syndrome (diagnosed according to Diagnostic and Statistical Manual IV criteria) who were receiving quetiapine therapy and had no diagnosis of epilepsy, major depression or psychotic disorder, were included in the study. The main outcome measure was the Yale Global Tic Severity Scale (YGTSS) score.

RESULTS

The initial dose of quetiapine was 25 mg/day, but the mean dose was increased to 114.6 +/- 51.6 mg/day and 175.0 +/- 116.8 mg/day at the fourth and eighth weeks of treatment, respectively. The YGTSS score, which was 21.6 +/- 4.0 at baseline, showed significant decreases at 4 and 8 weeks (reducing to 7.5 +/- 7.4 and 5.6 +/- 8.1, respectively; p < 0.003). Routine laboratory parameters and serum prolactin level were all normal and did not change throughout treatment. Mild but significant increases in both bodyweight and body mass index at 4 and 8 weeks compared with baseline were observed.

CONCLUSION

Other than causing mild weight gain, quetiapine appears to be an effective, safe and well tolerated drug in children and adolescents with Tourette's syndrome.

Review of antipsychotics in children and adolescents

The use of antipsychotics in children and adolescents in the clinical setting is increasing. This article reviews 77 clinical trials published in the last 10 years, investigating their efficacy, effectiveness, safety and pharmacokinetic data in paediatric populations. The diagnostic categories in which the antipsychotics are commonly used (schizophrenia, pervasive developmental disorders, Tourette's disorder, mental retardation/subaverage intelligence, mood disorders and disruptive behaviour disorders) were used in order to review the evidence and effectiveness. All randomised, double-blind, placebo-controlled trials from the past decade are also summarised. This review refers to recent relevant practice parameters, guidelines and reviews throughout the text. Consistent with previous reviews, it is concluded that the recent trend of increased use of antipsychotics in children and adolescents is not adequately supported by evidence. Specific suggestions have been provided on how to incorporate the existing evidence base into clinical decision making. The review ends with the authors' opinion on the clinical and research implications for the field and future directions.

Effectiveness, safety, and pharmacokinetics of quetiapine in aggressive children with conduct disorder

OBJECTIVE

To provide an initial description of the effectiveness and pharmacokinetics (PK) of quetiapine in aggressive children with conduct disorder (CD).

METHOD

This 8-week, open-label outpatient trial, enrolled patients ages 6 to 12 years with CD. Outcome measures included the Rating of Aggression Against People and/or Property Scale (RAAPPS), Nisonger Child Behavior Rating Form (NCBRF), and the Conners Parent Rating Scale (CPRS-48). Blood sampling for PK analyses occurred at the end of weeks 2 and 8.

RESULTS

Seventeen children (16 boys, mean age 8.9 years) were treated. The mean dose at week 8 was 4.4 mg/kg (SD = 1.1 mg/kg). Significant decreases in the baseline scores of the RAAPPS, and several subscales of the NCBRF and the CPRS were found by the end of the study (p <.05). No patients discontinued because of an adverse event. No patients experienced extrapyramidal side effects. Quetiapine disposition was linear over the dose range studied. The elimination half-life of the drug averaged 3.9 and 2.9 hours and total body clearance averaged 3.5 and 3.0 L/hr/kg after study weeks 2 and 8, respectively.

CONCLUSIONS

These preliminary data suggest that aggressive children with CD may benefit from quetiapine. The PK of quetiapine supports twice-daily dosing in children with CD.

Separable noradrenergic and dopaminergic regulation of prepulse inhibition in rats: implications for predictive validity and Tourette Syndrome

INTRODUCTION

Startle inhibition by lead stimuli (prepulse inhibition, "PPI"), and the disruption of this process by dopamine agonists and N-methyl-D: -aspartate (NMDA) antagonists, are used in predictive models for antipsychotic development. PPI is also disrupted by the norepinephrine alpha-1 agonist, cirazoline, and the PPI-disruptive effects of the indirect dopamine agonist amphetamine are opposed by the norepinephrine reuptake inhibitor, desipramine. The hypothesis that PPI may be regulated by norepinephrine, or by interactions between dopamine and norepinephrine substrates, was tested in a series of experiments with the alpha-2 agonist, clonidine, which is used clinically to treat Tourette Syndrome (TS).

MATERIALS AND METHODS

PPI was measured in male Sprague-Dawley rats after pretreatment with clonidine or the D2 antagonist haloperidol, and treatment with cirazoline, amphetamine, the D1/D2 agonist apomorphine, or the NMDA antagonist, phencyclidine.

RESULTS

PPI was disrupted by cirazoline; this effect was prevented by clonidine but not haloperidol. PPI was disrupted by apomorphine; this effect was prevented by haloperidol but not clonidine. Clonidine also failed to oppose the PPI-disruptive effects of amphetamine and augmented the PPI-disruptive effects of phencyclidine. Over a range of prepulse intervals, clonidine enhanced PPI at short intervals and opposed the PPI-disruptive effects of cirazoline at long intervals.

CONCLUSIONS

PPI is regulated by both norepinephrine and dopamine substrates that are neurochemically separable. The PPI-protective effects of clonidine suggest that the noradrenergic regulation of PPI may have utility for predicting therapeutic benefit in TS for drugs other than antipsychotics. Clonidine's failure to prevent the PPI-disruptive effects of apomorphine or phencyclidine further support the specificity of these PPI models for detecting drugs with antipsychotic properties.

Tourette's Syndrome

This article has focused on TS, and the relationship between TS and OCD has been addressed from different perspectives. In patients who have OCD, the presence of TS seems to have some impact in the clinical manifestation of OCD symptoms. One of the main features of tic-related OCD is the frequent presence of sensory phenomena preceding the compulsions, in the absence of obsessions. Genetic epidemiologic studies provide consistent evidence for the association between TS and OCD. Although no major loci have been identified so far, family and segregation analysis studies support the assumption that genes play a major role in the etiology of TS and related disorders. Genes interact with environmental factors,which can modulate the expression of TS or OCD and determine the onset of these disorders. Neuroimaging studies suggest that the pathophysiology of TS encompasses projections of primary, secondary, and somato sensory cortex to the putamen, dorsolateral caudate nucleus, and globus pallidus,whereas the pathophysiology of OCD involves more ventral structures,such as orbitofrontal-caudate-thalamic-cortical areas. Current treatment strategies for TS include education, behavioral therapy, pharmacotherapy,and support from patients associations. Alfa-adrenergic agents such as guanfacine and clonidine are first-choice treatments for TS; typical antipsychotics are more effective but are troublesome because of their long-term side-effect profiles. For comorbid TS plus OCD, each condition should be treated with its respective first-line option. Nonetheless, for patients who have tic-related OCD who are unresponsive to monotherapy with serotonin reuptake inhibitors, augmentation of serotonin reuptake inhibitors with atypical antipsychotics may be of benefit. Despite important advances, re-search is needed to clarify further the biologic and behavioral aspects of TS and its relationship with the frequently associated conditions, with particular attention to their management and prognosis.

Aripiprazole for the treatment of Tourette's disorder

OBJECTIVE

Tourette's disorder is a neuropsychiatric syndrome that manifests with motor and vocal tics, including coprolalia. This article presents a report of successful treatment of these tics with aripiprazole in 2 consecutive patients with Tourette's disorder.

METHOD

After an informed consent was obtained from the subjects, approval for this retrospective case series was sought from the Institutional Review Board. A detailed history was obtained and physical and mental state examination was performed for each patient. Tic severity was assessed using the Yale Global Tic Severity Scale. Aripiprazole was started at a low dose (5 mg/day) and titrated. The severity of tics was monitored during follow-up.

RESULTS

The 2 individuals presented in these case reports tolerated aripiprazole well and showed a clinically significant decrease in tic frequency and severity.

CONCLUSIONS

Aripiprazole, a newer atypical antipsychotic with a unique pharmacodynamic profile, appears to be efficacious in treatment of tics in Tourette's disorder, thus impressing upon the need for placebo-controlled trials in the management of this neuropsychiatric syndrome.

Contemporary assessment and pharmacotherapy of Tourette syndrome

To develop a guide to clinical assessment and pharmacotherapy for children and adults with Tourette syndrome (TS), we reviewed published literature over the past 25 years to identify original articles and reviews on the assessment and pharmacological treatment of Tourette syndrome, attention-deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). The literature search also included a survey of reviews published in book chapters. The assessment section was compiled from several reviews. Pharmacological treatments were classified into those with strong empirical support (as evidenced by two positive placebo-controlled studies for tics, OCD, or ADHD in TS samples); modest empirical support (one positive placebo-controlled study), or minimal support (open-label data only). We conclude that accurate diagnosis, including identification of comorbid conditions, is an essential step toward appropriate treatment for patients with TS. In many patients with TS, symptom management requires pharmacotherapy for tics or coexisting conditions. The evidence supporting efficacy and safety for medications used in patients with TS varies. But this evidence offers the best guide to clinical practice.

Recognizing and monitoring adverse events of second-generation antipsychotics in children and adolescents

Although second-generation antipsychotics (SGAs) are used increasingly in children and adolescents, data on the effectiveness and safety in pediatric populations are still sparse. Much of the safety information is derived from studies conducted in adults. This derivation is problematic because children and adolescents are exposed to SGAs during a phase of unparalleled physical and psychologic development that can affect pharmacokinetic and pharmacodynamic drug actions, efficacy, and side-effect patterns. This article presents an overview of SGA-related side effects in children and adolescents and strategies to monitor health outcomes effectively in youngsters receiving SGAs.

Tic disorders: from pathophysiology to treatment

Tic disorders are stereotypic behaviours,more frequent than once believed, and therefore likely to be encountered by primary care physicians. Tics usually begin in childhood and are the clinical hallmark of Tourette Syndrome (TS), the most common cause of tics. TS is a relatively common neurobehavioural disorder with a spectrum of manifestations that wax and wane during its natural course. The pathophysiology of tics, at molecular and cellular level, is still unknown,whereas structural and functional neuroimaging studies have shown the involvement of the basal ganglia and related cortico-striato-thalamo-cortical circuits, and the dopaminergic neuronal system. Moreover, TS has a strong genetic background. The management of TS is often complicated by the presence of attention-deficit/hyperactivity disorder, obsessive-compulsive disorder, and other behaviour disorders. The correct diagnosis is a fundamental step for a proper management of these disorders, and a multimodal treatment is usually indicated. This approach includes educational and supportive interventions, as well as pharmacological treatments when tics are at their worst.

Metabolic side effects of atypical antipsychotics in children: a literature review

The objective of this review is to summarize the data about metabolic side effects of atypical antipsychotics in children. Original research articles about side effects of atypical antipsychotics used in children were reviewed. The data was obtained mainly through Medline searches, identifying articles focusing on the use of atypical antipsychotics in children. Forty studies that addressed the issue of metabolic side effects were selected. The use of atypical antipsychotics in children has been consistently associated with weight gain and moderate prolactin elevation, while only a few case reports address the issue of glucose dysregulation and dyslipidaemia. The risk of weight gain and hyperprolactinaemia might be higher in younger children. Other risk factors have also been associated with antipsychotic-induced metabolic disturbances. These changes seem to be reversible, at least in some cases. Metabolic side effects of atypical antipsychotics could lead to serious complications in children who are prescribed these medications. Serious considerations should be given before initiating treatment and consistent clinical monitoring is essential. More research is needed, especially regarding glucose dysregulation and dyslipidaemia.

Using animal models to develop therapeutics for Tourette Syndrome

The science of Tourette Syndrome (TS) is advancing at multiple levels of analysis and will be enhanced through the use of animal models. Particular challenges in the development of TS animal models reflect complex features of this disorder, including its waxing and waning course and its "invisible" sensory and psychic symptoms. Animal models can achieve face, predictive, or construct validity based on their particular features. Predictive validity, of most direct relevance to drug development for TS, is achieved to some degree by a several animal models, although the reliance of most of these models on measures of motor suppression may ultimately limit their utility. Other models achieve construct validity with proposed pathophysiological mechanisms related to the immune and neural circuit etiologies of TS. One model-deficient sensorimotor gating of the startle reflex-is discussed in terms of its present and future applications towards advancing our understanding of the pathophysiology and treatment of TS. In addition to models that will advance the pharmacotherapy of TS, other animal models may enhance the utility of nonpharmacologic TS treatments, ranging from behavior therapy to deep brain stimulation (DBS).

Emerging drugs in Tourette syndrome

Proper education of the patient is the first step in the treatment of Tourette syndrome (TS). Before deciding how to treat the patient, it is important to decide whether to treat the TS-related symptoms. Counselling and behavioural modification may be sufficient for those with mild symptoms. Medications, however, may be considered when symptoms begin to interfere with peer relationships, social interactions, academic or job performance, or with activities of daily living. Therapy must be individualised and the most troublesome symptoms should be targeted first. Antidopaminergic agents are clearly the most effective drugs in the treatment of tics. Although haloperidol and pimozide are the only drugs currently approved by the FDA for the treatment of TS, other dopamine receptor-blocking drugs and tetrabenazine, a dopamine depleting drug, as well as botulinum toxin injections, have been used to treat tics associated with TS. Carefully designed, comparative, longitudinal trials assessing the efficacy and adverse-effect profiles of these drugs, including tardive dyskinesia, are lacking. Selective serotonin reuptake inhibitors are recommended for the treatment of obsessive-compulsive behaviour: a common comorbidity. Psychostimulants, such as methylphenidate, are the treatment of choice for attention deficit hyperactivity disorder. Even though these drugs may transiently increase tics, this does not necessarily constitute a definite contraindication to the use of these drugs in patients with TS. Here, existing and emerging medical treatments in patients with tics and comorbid behavioural disorders associated with TS are reviewed.