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Diagnostic Features

The essential features of Tourette's Disorder are multiple motor tics and one or more vocal tics (Criterion A). These may appear simultaneously or at different periods during the illness. The tics occur many times a day, recurrently throughout a period of more than 1 year (Criterion B). During this period, there is never a tic-free period of more than 3 consecutive months. The disturbance causes marked distress or significant impairment in social, occupational, or other important areas of functioning (Criterion C). The onset of the disorder is before age 18 years (Criterion D). The tics are not due to the direct physiological effects of a substance (e.g., stimulants) or a general medical condition (e.g., Huntington's disease or postviral encephalitis) (Criterion E).

The anatopical location, number, frequency, complexity, and severity of the tics change over time. The tics typically involve the head and, frequently, other parts of the body, such as the torso and upper and lower limbs. The vocal tics include various words or sounds such as clicks, grunts, yelps, barks, sniffs, snorts, and coughs. Coprolalia, a complex vocal tic involving the uttering of obscenities, is present in a few individuals (less than 10%) with this disorder. Complex motor tics involving touching, squatting, deep knee bends, retracing steps, and twirling when walking may be present. In approximately one-half the individuals with this disorder, the first symptoms to appear are bouts of a single tic, most frequently eye blinking, less frequently tics involving another part of the face or the body. Initial symptoms can also include tongue protrusion, squatting, sniffing, hopping, skipping, throat clearing, stuttering, uttering sounds or words, and coprolalia. The other cases begin with multiple symptoms.

Associated Features and Disorders

The most common associated symptoms of Tourette's Disorder are obsessions and compulsions. Hyperactivity, distractibility, and impulsivity are also relatively common. Social discomfort, shame, self-consciousness, and depressed mood frequently occur. Social, academic, and occupational functioning may be impaired because of rejection by others or anxiety about having tics in social situations. In sever cases of Tourette's Disorder, the tics may directly interfere with daily activities (e.g., reading or writing). Rare complications of Tourette's Disorder include physical injury, such as blindness due to retinal detachment (from head banging or striking oneself), orthopedic problems (from knee bending, neck jerking, or head turning), and skin problems (from picking). The severity of the tics may be exacerbated by administration of central nervous system stimulants, which may be a dose-related phenomenon. Obsessive-Compulsive disorder, Attention-Deficit/Hyperactivity Disorder, and Learning Disorders may be associated with Tourette's Disorder.

Specific Culture and Gender Features

Tourette's Disorder has been widely reported in diverse racial and ethnic groups. The disorder is approximately 1.5-3 times more common in males than in females.

Prevalence

Tourette's Disorder occurs in approximately 4-5 individuals per 10,000.

Course

The age at onset of Tourette's Disorder may be as early as age 2 years, is usually during childhood or early adolescence, and is by definition before age 18 years. The median age at onset for motor tics is 7 years. The duration of the disorder is usually lifelong, though periods of remission lasting from weeks to years may occur. In most cases, the severity, frequency, and variability of the symptoms diminish during adolescence and adulthood. In other cases, the symptoms disappear entirely, usually by early adulthood.

Familial Pattern

The vulnerability to Tourette's Disorder and related disorders is transmitted in an autosomal dominant pattern. "Vulnerability" implies that the child receives the genetic or constitutional basis for developing a Tic Disorder; the precise type or severity of disorder may be different from one generation to another. Not everyone who inherits the genetic vulnerability will express symptoms of a Tic Disorder. Penetrance in female gene carriers is about 70%; penetrance in male gene carriers is about 99%. The range of forms in which the vulnerability may be expressed includes full-blown Tourette's Disorder, Chronic Motor or Vocal Tic Disorder, some forms of Obsessive-Compulsive Disorder, and, perhaps, Attention-Deficit/Hyperactivity Disorder. In about 10% of those with Tourette's Disorder, there is no evidence of a familial pattern. Individuals with these "nongenetic" forms of Tourette's Disorder or another tic disorder often have another mental disorder (e.g., Pervasive Developmental Disorder) or a general medical condition (e.g., a seizure disorder).

Differential Diagnosis

Refer to the "Differential Diagnosis" section for Tic Disorders (p. 100). [NOTE: This refers to a page number in the original text. The pertinent section has been reproduced in the next paragraph.]

From Page 100:

Tic Disorders must be distinguished from other types of abnormal movements that may accompany general medical conditions (e.g., Huntington's disease, stroke, Lesch-Nyhan syndrome, Wilson's disease, Sydenham's chorea, multiple sclerosis, postviral encephalitis, head injury) or may be due to the direct effects of a substance (e.g., a neuroleptic medication).

1. Choreiform movements are dancing, random, irregular, nonrepetitive movements.
2. Dystonic movements are slower, twisting movements interspersed with prolonged states of muscular tension.
3. Athetoid movements are slow, irregular, writhing movements, most frequently in the fingers and toes, but often involving the face and neck.
4. Myoclonic movements are brief, shocklike muscle contractions that may affect parts of muscles or muscle groups but not synergistically.
5. Hemiballismic movements are intermittent, coarse, large-amplitude, unilateral movements of the limbs.
6. Spasms are stereotypic, slower, and more prolonged than tics and involve groups of muscles.
7. Hemifacial spasm consists of irregular, repetitive, unilateral jerks of facial muscles.
8. Synkinesis involves an involuntary movement accompanying a voluntary one (e.g., movement of the corner of the mouth when the person intends to close the eye.) This differentiation is further facilitated by considering the presence of features of the underlying general medical condition (e.g., characteristic family history in Huntington's disease) or a history of medication use.

When tics are a direct physiological consequence of medication use, a Medication-Induced Movement Disorder Not Otherwise Specified would be diagnosed instead of a Tic Disorder. In some cases, certain medications (e.g., methylphenidate) may exacerbate a preexisting Tic Disorder, in which case no additional diagnosis of a medication-induced disorder is necessary.

Tics must also be distinguished from stereotyped movements seen in Stereotypic Movement Disorder and Pervasive Developmental Disorders. Differentiating simple tics (e.g., eye blinking) from the complex movements characteristic of stereotyped movements is relatively straightforward. The distinction between complex motor tics and stereotyped movements is less clear-cut. In general, stereotyped movements appear to be more driven and intentional, whereas tics have a more involuntary quality and are not rhythmic. Tics must be distinguished from compulsions (as in Obsessive-Compulsive Disorder). Compulsions are typically quite complex and are performed in response to an obsession or according to rules that must be applied rigidly. In contrast to a compulsion, tics are typically less complex and are not aimed at neutralizing the anxiety resulting from an obsession. Some individuals manifest symptoms of both Obsessive-Compulsive Disorder and a Tic Disorder (especially Tourette's Disorder), so that both diagnoses may be warranted. Certain vocal or motor tics (e.g., barking, echolalia, palilalia) must be distinguished from disorganized or catatonic behavior in Schizophrenia.

The Tic Disorders can be distinguished from one another based on duration and variety of tics and age at onset. Transient Tic Disorder includes motor and/or vocal tics lasting for at least 4 weeks but for no longer than 12 consecutive months. Tourette's Disorder and Chronic Motor or Vocal Tic Disorder each have a duration of more than 12 months but are distinguished by the requirement for Tourette's Disorder that there be multiple motor tics and at least one vocal tic. Tic Disorder Not Otherwise Specified would be appropriate for clinically significant presentations lasting less than 4 weeks, for presentations with an age at onset above age 18 years, and for the unusual case of an individual with only one motor tic and only one vocal tic.