Type of psychology: Psychopathology

Field of study: Nervous system

Tourette’s syndrome is classified as a neuropsychiatric disorder because of its roots in neurological functioning, but its prominent features relate to a person’s behavior and psychological/psychiatric functioning. The disorder is characterized by motor tics of the face, head, and other extremities that persist for more than one year. There are typically behavioral and cognitive symptoms linked to attention-deficit hyperactivity disorder and obsessive-compulsive disorder.

Introduction

Tourette’s syndrome is named for Georges Gilles de la Tourette, the French physician who described the syndrome extensively in 1885. Tourette was the first to describe and publish a case study of a noblewoman who had the disorder. He later identified many of the symptoms that remain associated with the syndrome, including multiple tics, echolalia (the repetition of what is said by other people as if the patient was producing an echo of the other person’s speech), and coprolalia (the use of obscene and vulgar language, often in a sexual context). The syndrome is considered to be rare, although estimates suggest it may occur in as many as one in two hundred individuals. Accurate estimates are difficult because of the variability of expression of the condition and the occurrence of multiple tics due to other causes. The incidence of Tourette’s syndrome is much higher in children than in adults, and in many cases, motor and vocal tics disappear in adulthood. The incidence of Tourette’s syndrome is greater in men than in women, as the generally accepted ratio of male to female patients is 4:1.

The onset of Tourette’s syndrome usually occurs in childhood, with the average age of onset being seven years, although cases can occur earlier or later. Typically, the symptoms initially are simple motor tics and progress to more complex motor and vocal tics, although there is considerable variability among patients. The tics often go through periods of waxing and waning, and reach their peak around age ten, after which point they decrease and often disappear in later adolescence.

When Tourette first characterized the syndrome in 1885, he described symptoms in multiple members of a single family. The genetic basis of Tourette’s syndrome is still not completely understood, but family studies have indicated that biological relatives of patients appear to have significantly greater risk of developing the syndrome than do relatives of unaffected persons.

Although there is no cure for Tourette’s syndrome, medications have been found to be useful in reducing tics and some of the associated abnormal behaviors. However, many medical practitioners hesitate to prescribe these medications unless symptoms significantly interfere with an individual’s day-to-day functioning. Haloperidol is the most well-known medication used to treat Tourette’s syndrome.

A surgical procedure called deep brain stimulation (DBS) has yielded promising results by substantially reducing or eliminating tics in affecting individuals. However, this procedure is still experimental and not yet an available or recommended form of treatment.

Clinical Features

The presence of motor and vocal tics in young children is not uncommon, occurring in up to 19 percent of children. The type, frequency, and duration of tics are important in classifying the type of disorder that may be affecting a child. The American Psychiatric Association’s Diagnostic and Statistic Manual of Mental Disorders: DSM-IV-TR (rev. 4th ed., 2000) lists four disorders that involve the presence of motor or vocal tics. Tourette’s syndrome is considered as a diagnosis when both motor and vocal tics persist for more than one year. The diagnostic criteria for Tourette’s syndrome include multiple motor and one or more vocal tics that have been present at some time during the illness, although not necessarily concurrently. The tics occur many times during a day (usually in bouts), nearly every day or intermittently throughout a period of more than a year. The anatomic location, number, frequency, complexity, and severity of the tics may change over time. There is usually a rostral to caudal movement (from the head to the trunk of the body) of tics that will repeat itself. Onset occurs before the age of eighteen. Occurrence is not exclusively during psychoactive substance intoxication or due to known central nervous system disease, such as Huntington chorea and postviral encephalitis.

The tics that are associated with Tourette’s syndrome may be motor tics if movements are involved, or they may be vocal tics if sound is produced. The syndrome commonly begins with facial tics such as blinking, grimacing, and nose twitching. Other involuntary movements may involve head shaking, arm flapping, shoulder shrugging, and foot movements. Head banging and other forms of self-abuse may occur, although these are quite rare. Tics may be simple, as is the case with eye blinking. They may be complex and involve a number of muscle groups, such as jumping up and down or imitating movements of another person. Simple tics tend to be replaced by complex tics, and the severity and frequency of tics tends to wax and wane over time. This can be the most puzzling aspect of the disorder, and research has suggested it is very difficult to predict the course of the tics over time. In some situations, tics are initially mild but become more severe, and in other situations, they may remit for undetermined periods of time. Tics tend to worsen under conditions of stress and tend to subside when the patient is concentrating on some task or activity. Rarely are they present during sleep. As individuals age, it becomes possible to suppress the tics with voluntary effort. A burst of tics generally follows the period of conscious suppression to relieve the mounting inner urge. Some people with Tourette’s syndrome have been able to have successful careers as actors, professional athletes, and surgeons.

The most severe aspects of Tourette’s syndrome, from a social point of view, are coprolalia and copropraxia (an involuntary use of obscene gestures). Although it is a common belief, it is not correct to think that coprolalia and copropraxia are found in nearly all people with Tourette’s syndrome. In fact, coprolalia is found in less than one-third of the cases, and copropraxia is far less common.

Most individuals with Tourette’s syndrome have other mental health concerns, although the severity of these issues varies considerably. The two most common comorbid conditions include attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). Studies have suggested that ADHD occurs in 50 to 60 percent of individuals with Tourette’s syndrome and typically develops before the onset of tics. The incidence of OCD and Tourette’s syndrome occurs in 30 to 70 percent of cases. OCD symptoms become more evident as the child matures and in many cases become the primary clinical issue in late adolescence and adulthood. The OCD symptoms in individuals with Tourette’s syndrome are more often described as sensorimotor compared with individuals with just OCD. That is, individuals with Tourette’s syndrome report physical sensations before tics or repetitive behaviors, whereas individuals with OCD describe specific thoughts and anxiety before compulsive behaviors. Although Tourette’s syndrome is a chronic disorder, symptoms are usually much more severe in childhood, with the severity of tics peaking by about ten years of age. The tics tend to improve or disappear entirely in more than half of affected adults.

Etiology

The cause of Tourette’s syndrome is not known. It represents a unique diagnosis that involves both neurology and psychiatry. For much of its history, Tourette’s syndrome was considered primarily a psychiatric disorder because of the presence of motor and vocal tics and other atpyical behaviors often associated with the syndrome. Psychiatric comorbidity does appear to be a primary feature of Tourette’s syndrome, but it is often a secondary consequence of the emotionally disabling physical features. As effective treatment with medications came into use, it became apparent that there was an underlying biochemical basis for the syndrome. The drug haloperidol, which is a dopamine receptor blocker, gave good results in controlling tics, indicating that somehow there was an increased sensitivity of the dopamine system in patients with Tourette’s syndrome. Some research suggests that serotonin also plays a role in Tourette’s syndrome, but the primary neurotransmitter of interest is dopamine. Other studies have found some evidence of subtle structural abnormalities in the basal ganglia of the brain. Recent experimental procedures have successfully used deep brain stimulation (DBS) on medial regions of the thalamus, a region with connections to the basal ganglia and brain cortex. The preliminary success of this procedure underscores the basal ganglia as an important brain structure involved in Tourette’s syndrome. There have been surprisingly few autopsies to study Tourette’s syndrome patients. Both gross and fine anatomical studies have not yielded conclusive findings, but results indicate that multiple structures of the brain may be involved in the syndrome.

Although a familial association of Tourette’s syndrome has long been known, two problems have contributed to the difficulty of genetic studies: the problem of variable expressivity and the problem of incomplete penetrance. With variable expressivity, there is a range of phenotypes resulting from a given genotype, and this is very characteristic of Tourette’s syndrome, where clinical features range from very mild to very severe. In incomplete penetrance, a genotype that should give rise to a certain expression or phenotype is not expressed at all, and this also seems to be true of Tourette’s syndrome. In addition, there is no universal agreement as to what the Tourette syndrome phenotype is. In spite of the limitations, considerable progress has been made in the understanding of the inheritance of Tourette’s syndrome.

The agreement between Tourette’s syndrome exhibited by both members of monozygotic twins is about 50 percent, compared to 10 percent for dizygotic twins. Since the value for monozygotic twins is less than 100 percent, this indicates that nongenetic and environmental factors play a role in etiology.

Most family studies indicate that Tourette’s syndrome is probably due to an autosomal dominant gene with incomplete penetrance. Although simple tics do not seem to have a familial relationship, severe tics do show such a relationship, with relatives of a patient being at an increased risk for tics, if not necessarily severe tics. Relatives of patients also are at increased risks for ADHD and OCD, indicating a possible genetic relationship of the disorders. Although the human genome has been scanned, no single gene has been found that is associated with Tourette’s syndrome.

Treatment

No medication has been found to eliminate the symptoms of Tourette’s syndrome completely. Good progress has been made in using medications in controlling and improving motor and vocal tics and some of the behavioral symptoms. Haloperidol acts as a depressant of the central nervous system and is successful in helping suppress symptoms in many patients. Side effects of haloperidol include drowsiness and alterations in mood, and may be severe enough to limit its use. Also, the effectiveness of haloperidol tends to diminish over time in many patients. Other drugs in use may have fewer side effects than haloperidol, but all drugs may have side effects. If behavioral disorders such as OCD and ADHD present problems, other medications such as risperidone (Risperdal) may need to be prescribed. In general, physicians are reluctant to prescribe medications unless the tics are severe and significantly affecting an individual’s daily functioning. The combination of cognitive behavior therapy and medication yields the most significant improvements in children. Other nondrug treatments, such as adaptations to diet, have been recommended.

Since the symptoms of Tourette’s syndrome may change over time, it is critical to monitor the levels of medications employed. Since Tourette’s syndrome can be a chronic and potentially a socially debilitating disorder, supportive psychotherapy should be available for not only patients but also their families. Until the inheritance of Tourette’s syndrome is understood more fully, genetic counseling will continue to be difficult. General information about recurrence risks and gender differences in the incidence of Tourette’s syndrome may be transmitted. It also is essential to inform family members and patients of the variability of expression of the disorder in patients and how symptoms may change over time in the same individual.

Sources for Further Study