The early course of the Tourette's syndrome clinical spectrum

Neural substrates of self-regulatory control in children and adults with Tourette syndrome

OBJECTIVE

To identify the neural substrate of self-regulatory control in children and adults with Tourette syndrome (TS).

METHOD

We used event-related functional magnetic resonance imaging (fMRI) to study the neural correlates of cognitive self-regulation during the Simon task. Forty-two people from The Tic Disorder Specialty Clinic who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for diagnosis with TS (24 children; 18 adults) were compared with 37 control subjects (19 children; 18 adults). Patients with TS were excluded from participation if they had any Axis I psychiatric disorder other than obsessive-compulsive disorder (OCD) or attention-deficit hyperactivity disorder (ADHD) prior to the onset of TS. Control participants were excluded if they reported a history of tic disorder, OCD, ADHD, or if they met diagnostic criteria for any Axis I disorder at the time of interview.

RESULTS

We detected greater overall fMRI activation in adults than in children across both diagnostic groups, primarily in frontal and striatal regions. In both groups we also detected an age-related shift away from more general cortical activation toward a more specific reliance on frontostriatal activity, a developmental correlate that was exaggerated in the TS group despite behavioural performances similar to those of control subjects. Moreover, the severity of tics correlated positively with frontal activations across age groups.

CONCLUSION

Frontostriatal circuits support cognitive and behavioural control. These circuits likely contribute both to optimal performance in this self-regulatory task and to the regulation of the severity of tics. Adults with persistent TS likely possess deficient activity in these circuits, attributable to either a failure of prefrontal plasticity or to disturbances in striatal functioning.

Obsessive-compulsive disorder: boundary issues

The boundaries between obsessive-compulsive disorder (OCD) and other neuropsychiatric disorders remain unresolved and may well differ from one disorder to another. Endophenotypes are heritable, quantitative traits hypothesized to more closely represent genetic risk for complex polygenic mental disorders than overt symptoms and behaviors. They may have a role in identifying how closely these disorders are associated with another and with other mental disorders with which they share major comorbidity. This review maps the nosological relationships of OCD to other neuropsychiatric disorders, using OCD as the prototype disorder and endophenotype markers, such as cognitive, imaging, and molecular data as well as results from demographic, comorbidity, family, and treatment studies. Despite high comorbidity rates, emerging evidence suggests substantial endophenotypic differences between OCD and anxiety disorders, depression, schizophrenia, and addictions, though comparative data is lacking and the picture is far from clear. On the other hand, strong relationships between OCD, Tourette syndrome, body dysmorphic disorder, hypochondriasis, grooming disorders, obsessive-compulsive personality disorder, and pediatric autoimmune neuropsychiatric disorders associated with streptococcus are likely. Studies designed to delineate the cause, consequences, and common factors are a challenging but essential goal for future research in this area.

Is obsessive-compulsive disorder an anxiety disorder?

Obsessive-compulsive disorder (OCD) is classified as an anxiety disorder in the DSM-IV-TR [American Psychiatric Association, 2000. Diagnostic and statistical manual of mental disorders, Fourth ed., rev. Washington, DC: Author]; however, the notion of a spectrum of obsessive-compulsive (OC) related disorders that is comprised of such disparate disorders as OCD, body dysmorphic disorder, certain eating disorders, pathological gambling, and autism, is gaining acceptance. The fact that these disorders share obsessive-compulsive features and evidence similarities in patient characteristics, course, comorbidity, neurobiology, and treatment response raises the question of whether OCD is best conceptualized as an anxiety or an OC spectrum disorder. This article reviews evidence from comorbidity and family studies, as well as biological evidence related to neurocircuitry, neurotransmitter function, and pharmacologic treatment response that bear on this question. The implications of removing OCD from the anxiety disorders category and moving it to an OC spectrum disorders category, as is being proposed for the DSM-V, is discussed.

Movement Disorders

This chapter covers five movement disorders: Parkinson's disease, dystonia, tic disorders, Huntington's disease, and essential tremor. These disorders demonstrate many of the most common challenges encountered in the epidemiologic investigation of movement disorders. Each section includes a description of the disease, followed by a review of descriptive studies (disease incidence, prevalence, and mortality studies), and discussion of genetic and environmental risk factors for the disorder. At the end of each section, directions for future studies are discussed.

Tourette's syndrome: are stimulants safe?

Clinicians commonly encounter children with comorbid attention deficit hyperactivity disorder (ADHD) and the tic disorder Tourette's syndrome. The pharmacologic treatment of children with this particular combination of conditions has been problematic because of long-standing warnings against using psychostimulants due to concerns about worsening tics. The basis for these warnings was anecdotal clinical observations. A recent group of placebo-controlled, double-blinded clinical trials have consistently shown that certain stimulants, particularly methylphenidate and dextroamphetamine, are effective, well tolerated, and safe when administered to treat ADHD in children with tics. Methylphenidate appears to be the best-tolerated stimulant compound, with tics often lessening during treatment.

Neuropsychiatric effects of guanfacine in children with mild tourette syndrome: a pilot study

The objective of this study was to evaluate the neuropsychiatric effects of the alpha-2a adrenergic agonist guanfacine in children with Tourette syndrome (TS). Twenty-four children with TS participated in a 4-week, double-blind, placebo-controlled study of guanfacine. Tic severity, neuropsychologic functioning, and parent ratings of behavior were evaluated pre- and post-treatment. The sample had mild tic severity and subtle neuropsychologic dysfunction pretreatment. Post-treatment, patients receiving guanfacine were rated by parents as significantly improved (compared to placebo) on one measure of executive function (parent-rated metacognition). Improvement on tic severity, performance-based neuropsychologic measures, and all other parent ratings were not significantly better than placebo. At a moderate dose and short-term treatment duration, guanfacine did not provide significant neuropsychiatric benefits in this group of children with mild TS.

The central role of magnesium deficiency in Tourette's syndrome: causal relationships between magnesium deficiency, altered biochemical pathways and symptoms relating to Tourette's syndrome and several reported comorbid conditions

Prior studies have suggested a common etiology involved in Tourette's syndrome and several comorbid conditions and symptomatology. Reportedly, current medications used in Tourette's syndrome have intolerable side-effects or are ineffective for many patients. After thoroughly researching the literature, I hypothesize that magnesium deficiency may be the central precipitating event and common pathway for the subsequent biochemical effects on substance P, kynurenine, NMDA receptors, and vitamin B6 that may result in the symptomatology of Tourette's syndrome and several reported comorbid conditions. These comorbid conditions and symptomatology include allergy, asthma, autism, attention deficit hyperactivity disorder, obsessive compulsive disorder, coprolalia, copropraxia, anxiety, depression, restless leg syndrome, migraine, self-injurious behavior, autoimmunity, rage, bruxism, seizure, heart arrhythmia, heightened sensitivity to sensory stimuli, and an exaggerated startle response. Common possible environmental and genetic factors are discussed, as well as biochemical mechanisms. Clinical studies to determine the medical efficacy for a comprehensive magnesium treatment option for Tourette's syndrome need to be conducted to make this relatively safe, low side-effect treatment option available to doctors and their patients.

Tics and its disorders

Tourette syndrome (TS) is familial neuropsychiatric disorder that is characterized by motor and phonic tics that begin in childhood. Once thought of as a rare and debilitating disorder, in the last decade new scientific knowledge suggests that TS and related tic disorders are more common and less debilitating for the majority of individuals. Evidence points toward a spectrum of TS symptomatology that extends beyond the tics disorder to probably include obsessive-compulsive disorder, attention deficit hyperactivity disorder, and mood disorders. Tourette syndrome and its differential diagnosis are discussed in this article with a focus on new developments in classification, etiology, epidemiology, genetics, pathophysiology, and clinical management.

Anxiety disorders and tic severity in juveniles with Tourette's disorder

OBJECTIVE

It was hypothesized that comorbidity with anxiety disorders would predict tic severity in youths with Tourette's disorder (TD).

METHOD

Subjects were 190 youths meeting DSM-III-R diagnostic criteria for TD who were consecutively referred to a pediatric psychopharmacology program between 1994 and 1997. Subjects were initially evaluated with a clinical interview and the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Epidemiologic version. Statistical analysis used t tests, chi 2 tests, and logistic regression analysis.

RESULTS

One hundred thirty-four subjects were classified as mild/moderate and 56 as severe TD cases. No meaningful differences were found in socioeconomic status, gender distribution, or age at onset of TD between the 2 groups. The 2 groups could not be differentiated by the presence of comorbid mood or disruptive behavior disorders including attention-deficit hyperactivity disorder. Although obsessive-compulsive disorder (OCD) was overrepresented among the severe TD cases, the difference failed to reach statistical significance. Excluding social and simple phobias, all other anxiety disorders were more clearly overrepresented among subjects with severe TD; separation anxiety disorder most robustly predicted tic severity, irrespective of the presence of OCD or other anxiety disorders.

CONCLUSION

Findings suggest that non-OCD anxiety disorders in general and separation anxiety disorder in particular may be significantly associated with tic severity in referred TD patients.

Psychophysiological aspects of Tourette's syndrome

Tourette's syndrome (TS), once considered a rare disorder, has been investigated extensively in the last two decades. It is inherited, usually beginning in childhood, and waxes and wanes, usually decreasing in frequency and severity in adolescence and early adulthood. Pharmacotherapy is the usual treatment approach, reducing frequency and severity of symptoms, but it is not a cure and often has side effects. Psychological help for people with TS and their families may be needed for this complex disorder.

Tourette's syndrome and psychopathology in a child psychiatry setting

Prior investigations of psychopathology among children with Tourette's syndrome (TS) have rarely used child psychiatry samples and sophisticated personality instruments.

OBJECTIVE

To produce an objectively derived composite TS personality profile and to determine the rate of particular problems in a TS psychiatry sample compared with children with out TS from the same clinical practice.

METHOD

Children (n = 33) referred to child psychiatrists because of emotional and behavior problems who were subsequently also found to meet DSM-III-R criteria for TS were assessed by the Personality Inventory for Children.

RESULTS

Children with TS expressed high rates of psychopathology overall (composite 2.7 SD elevated) with depression, anxiety, and peculiar behavior having the highest values; depression occurred most frequently (73%), and attention-deficit hyperactivity disorder (55%) was no more common than among comparison group children and conduct problems (18%) were rarer. "Depression, anxiety, tension, and excessive worry" were characteristic of the actuarially derived modal TS personality.

CONCLUSIONS

The prevalence and manifestations of psychopathology of children with TS in a child psychiatry practice are not identical with those reported in the literature. Child psychiatrists should be particularly vigilant of depressive symptoms and expect to encounter relatively few conduct problems compared with children without TS. Establishing "local prevalence rates" for children with TS seeking psychiatric evaluation can help guide the diagnostician and make diagnosis more assured.

The course and prognosis of Tourette syndrome

The view of Tourette syndrome as a lifelong disorder, once held as a certainty, has changed considerably in the past two decades. It is now known that in the majority of cases, tics will ebb in severity and will no longer be problematic in the adult years. This discovery, however, has been accompanied by the realization that Tourette syndrome is a far more complex disorder than was originally discerned and that it has many unanswered questions.

Epidemiology of Tourette syndrome

The epidemiology of Tourette syndrome is difficult to characterize because there is no definitive diagnosis. Symptom intensity and frequency decrease with age and in social situations, and affected individuals are often unaware of their tics. This chapter reviews and summarizes current data on the prevalence, distribution, and risk factors for Tourette syndrome.

Attention deficit hyperactivity disorder in the presence of Tourette syndrome

Increasing attention to comorbidity in Tourette syndrome has led to a search for factors that would help in the development of treatment strategies for attention deficit hyperactivity disorder. Despite arguments and some research supporting various viewpoints, it is still unclear to what extent the frequency of co-occurrence is high in Tourette syndrome. It also is unclear whether attention deficit hyperactivity disorder and obsessive-compulsive disorder are part of a spectrum with related genetic or environmental factors. One of the main difficulties is obtaining a truly representative community sample and agreeing upon the categorical boundaries. The consequences of this argument are discussed. Effective treatment of attention deficit hyperactivity disorder in the presence of tics and Tourette syndrome has undergone considerable change from an absolute contraindication of stimulants to cautious use. For those whom stimulants fail or produce unacceptable side effects, nonstimulant medications are available in increasing variety. Much more methodologically adequate research needs to be undertaken with them.

Social and educational resources for patients with Tourette syndrome

Patients with Tourette syndrome may experience significant behavioral, academic, social, and vocational difficulty. Early diagnosis and a comprehensive treatment plan which includes the school and family may prevent exacerbation of tic symptoms and behavior problems. Since the extent of impairment frequently is unrelated to the severity of any observed or reported tics, clinicians evaluating a child or adolescent who presents with tics or a history of tics should include assessment of family dynamics, a description of any school-based or peer problems, and an evaluation for motor deficits as well as determination of whether features of any associated or comorbid disorders are present. The clinician provides vital services as an educator and advocate for the patient and as a guide in directing the family and patient to available social, educational, and vocational resources.

A Brazilian cohort of patients with Tourette's syndrome

The clinical features of 32 patients (24 males) with Tourette's syndrome in Brazil were studied. The mean age at onset was 7.1 years, tics being the first symptom in 71% and hyperactivity in 29%. Blinking, grimacing, and shoulder elevation were the most common motor tics and sniffing, throat clearing, and grunting noises, the most frequent vocal tics. Coprolalia was present in 28%, echolalia in 16%, palilalia in 9%, and copropraxia in 25% of patients. Attention deficit and hyperactivity disorder was diagnosed in 63%, and obsessive compulsive behaviour in 44% of patients. In 84% of patients there was a family history of tics whereas attention deficit and hyperactivity disorder and obsessive compulsive behaviour were respectively present in relatives of 19% and 53% of the patients studied. These data suggest that Tourette's syndrome in Brazil is not clinically different from other countries, supporting the notion that genetic factors play the most important part in its aetiology.

The relationship between tic disorders and Tourette's syndrome revisited

OBJECTIVE

The relationship between Tourette's syndrome (TS) and chronic tic disorder is of great clinical and scientific importance because of uncertainties in both prognosis and pharmacotherapeutic strategies. One approach to evaluating the relationship between TS and chronic tics is to examine whether they share similar neuropsychological and psychiatric correlates.

METHOD

Children with TS (n = 32) and children with chronic tics (n = 39) were ascertained from an unselected sample of the children referred for psychopharmacological treatment and examined using standardized diagnostic assessments and testing procedures.

RESULTS

Children with TS and those with chronic tics were similar to each other and different from controls in clinical correlates that included psychiatric comorbidity, as well as school, neuropsychological, and psychosocial impairments. Patients with TS also had higher rates of obsessive-compulsive disorder, oppositional defiant disorder, and simple phobia than did patients with chronic tic disorder.

CONCLUSIONS

These findings indicate that TS and chronic tic disorder are part of the same disease entity, with TS being a more severe form of tic disorder.

Neurobiological issues in Tourette syndrome

The Tourette syndrome (TS) represents an intriguing disorder that overlaps the clinical fields of neurology and psychiatry. Composed of a spectrum of familial, involuntary motor and vocal tics and co-morbid neuropsychological problems, this disorder has become a model for investigators interested in neurobehavioral research. Although the subject of numerous reports since Tourette's original description in 1885, over the past decade there has been a rapid expansion of knowledge pertaining to the phenomenology of tic syndromes and their associated problems, the role of genetic and environmental factors, and the underlying pathophysiology. The role of frontal-subcortical circuits, dopaminergic neurotransmission, and second messenger systems are highlighted. This report provides a framework for understanding current neurobiological issues in TS.