Tourette's disorder

307.23 Tourette's Disorder

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. During this period, there is never a tic-free period of more than 3 consecutive months (Criterion B). The onset of the disorder is before age 18 years (Criterion C). 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 D).

The anatomical location, number, frequency, complexity, and severity of the tics change over time. Simple and complex motor tics may affect any part of the body, including the face, head, torso, and upper and lower limbs. Simple motor tics are rapid, meaningless contractions of one or a few muscles, such as eye blinking. Complex motor tics involving touching, squatting, deep knee bends, retracing steps, and twirling when walking may be present. 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 only a small minority of individuals (less than 10%) and is not required for a diagnosis of Tourette's Disorder.

In approximately one-half of the individuals with this disorder, the first symptoms to appear are bouts of a single tic, most frequently eye blinking. Less frequently, initial tics involve another part of the face or the body, such as facial grimacing, head jerking, tongue protrusion, sniffing, hopping, skipping, throat clearing, stuttering-like block in speech fluency, or uttering sounds or words. Sometimes this disorder begins with multiple symptoms starting at the same time.

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 demoralization and sadness frequently occur. Persistent motor and vocal tics may cause a broad range of distress and impairment, ranging from none to severe. Younger children, in particular, may be unaware of their tics, suffer no distress, and show no impairment in any area of functioning. A high percentage of children, adolescents, and adults with Tourette's Disorder do not seek medical attention for their tics. At the other end of the spectrum, there are individuals with Tourette's Disorder who are burdened by intrusive, recurrent, forceful, and socially stigmatizing motor and vocal tics.

Social, academic, and occupational functioning may be impaired because of rejection by others or anxiety about having tics in social situations. Chronic tic symptoms can cause considerable distress and can lead to social isolation and personality changes. In severe cases of Tourette's Disorder, the tics may directly interfere with daily activities (e.g., conversing, reading, or writing). Rare complications of Tourette's Disorder include physical injury, such as blindness due to self-inflicted eye injury (from head banging or eye gouging), orthopedic problems (from knee bending, neck jerking, or head turning), skin problems (from picking or lip licking), and neurological sequelae (e.g., from disc disease related to many years of forceful neck movements). The severity of the tics may be exacerbated by administration of central nervous system stimulants, such as those used in the treatment of Attention-Deficit/Hyperactivity Disorder, although some individuals can tolerate these medications without an exacerbation of their tics or may even have a reduction in tics. Obsessive-Compulsive Disorder and Attention-Deficit/Hyperactivity Disorder often co-occur in individuals with Tourette's Disorder. Attentional problems or obsessive symptomatology may precede or follow the onset of tics. Obsessive-compulsive symptoms found in individuals with Tourette's Disorder may constitute a specific subtype of Obsessive-Compulsive Disorder. This subtype appears to be characterized by an earlier age at onset, male preponderance, higher frequency of certain obsessive-compulsive symptoms (more aggressive symptoms and less concern about contamination and hoarding), and poorer response to pharmacotherapy with selective serotonin reuptake inhibitors. Disruptive behavior, impulsiveness, and social immaturity are prominent features in those children and adolescents who also have Attention-Deficit/Hyperactivity Disorder. These clinical features may interfere with academic progress and interpersonal relationships and lead to greater impairment than that caused by the Tourette's Disorder.

Specific Culture and Gender Features

Tourette's Disorder has been widely reported in diverse racial and ethnic groups. Although in clinical settings the disorder is diagnosed approximately three to five times more often in males than in females, the gender ratio is perhaps as low as 2:1 in community samples.

Prevalence

The prevalence of Tourette's Disorder is related to age. Many more children (5-30 per 10,000) are affected than adults (1-2 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 about 6-7 years. The duration of the disorder may be lifelong, though periods of remission lasting from weeks to years may occur. In most cases, the severity, frequency, disruptiveness, and variability of the symptoms diminish during adolescence and adulthood. In other cases, the symptoms actually disappear entirely, usually by early adulthood. In a few cases, the symptoms may worsen in adulthood. The predictors of this course are not known.

Familial Pattern

The vulnerability to Tourette's Disorder and related disorders is transmitted within families and appears to be genetic. The mode of genetic transmission, however, is not known. Pedigree studies suggest that there are genes of major effect. Although some early studies suggested a pattern of transmission that is consistent with an autosomal dominant pattern, other studies suggest a more complex mode of transmission. "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 and is modified by nongenetic factors. Not everyone who inherits the genetic vulnerability will express symptoms of a Tic Disorder. The range of forms in which the vulnerability may be expressed includes Tourette's Disorder, Chronic Motor or Vocal Tic Disorder, and some forms of Obsessive-Compulsive Disorder. It also appears that individuals with Tourette's Disorder are at greater risk for Attention-Deficit/Hyperactivity Disorder. In some individuals with Tourette's Disorder, there is no evidence of a familial pattern.

Differential Diagnosis

Refer to the "Differential Diagnosis" section for Tic Disorders (p. 110).

Diagnostic criteria for 307.23 Tourette's Disorder

Both multiple motor and one or more vocal tics have been present at some time during the illness, although not necessarily concurrently. (A tic is a sudden, rapid, recurrent, nonrhythmic, stereotyped motor movement or vocalization.)
The tics occur many times a day (usually in bouts) nearly every day or intermittently throughout a period of more than 1 year, and during this period there was never a tic-free period of more than 3 consecutive months.
The onset is before age 18 years.
The disturbance is 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).