Tics are the essential feature of the three disorders in this subclass: Tourette's Disorder, Chronic Motor or Vocal Tic Disorder, and Transient Tic Disorder. There is evidence from genetic and other studies that Tourette's Disorder and Chronic Motor or Vocal Tic Disorder represent different symptomatic expressions of the same underlying disorder. However, they are included in this manual as separate disorders because they generally involve different degrees of impairment (the former being more disabling) and they have different treatment implications.
A tic is an involuntary, sudden, rapid, recurrent, nonrhythmic, stereotyped, motor movement or vocalization. It is experienced as irresistible, but can be supressed for varying lengths of time. All forms of tics are exacerbated by stress and usually are markedly diminished during sleep. They may become attenuated during some absorbing activities, such as reading or sewing.
Both motor and vocal tics may be classified as either simple or complex, although the boundaries are not well defined. Common simple motor tics are eye-blinking, neck-jerking, shoulder-shrugging and facial grimacing. Common simple vocal tics are coughing, throat-clearing, grunting, sniffing, snorting and barking. Common complex motor tics are facial gestures, grooming behaviors, hitting or biting self, jumping, touching, stamping and smelling an object. Common complex vocal tics are repeating words or phrases out of context, coprolalia (use of socially unacceptable words, frequently obscene), palilalia (repeating one's own sounds or words), and echolalia (repeating the last-heard sound, word or phrase of another person or a last-heard sound). Other complex tics include echokinesis (imitation of the movements of someone who is being observed).
Associated features. Discomfort in social situations, shame, self-consciousness and depressed mood are common, especially with Tourette's Disorder.
Predisposing factors. A controversy exists as to whether or not the onset of some cases of Tic Disorders is precipitated by exposure to phenothiazines, head trauma or the administration of central nervous system stimulants. It is estimated that in one-third of cases of Tourette's Disorder, the severity of the tics is exacerbated by administration of central nervous system stimulants, which may be a dose-related phenomenon.
Impairment. Social, academic and occupational functioning may be impaired because of rejection by others or anxiety about having tics in social situations. In addition, in severe cases of Tourette's Disorder, the tics themselves may interfere with daily activities such as reading or writing. Although most people with Tourette's Disorder do not have marked impairment, in general the impairment is more severe than in Chronic Motor or Vocal Tic Disorder. Impairment in Transient Tic Disorder rarely is marked.
Differential diagnosis of tics. Tics should be
distinguished from other movement
disturbances. Choreiform movements are
dancing, random, irregular, nonrepetitive movements.
Dystonic movements are slower, twisting movements
interspersed with prolonged states of muscular tension.
Athetoid movements are slow, irregular, writhing
movements, most frequently in the fingers and toes, but often
involving the face and neck. Myoclonic movements
are brief, shocklike muscle contractions that may affect
parts of muscles or muscle groups, but not synergistically.
Hemiballismic movements are intermittent, coarse,
large amplitude, unilateral movements of the limbs.
Spasms are stereotypic, slower and more prolonged
than tics and involve groups of muscles. Hemifacial
spasm consists of irregular, repetitive, unilateral jerks
of facial muscles. Synkinesis consists of
movements of the corner of the mouth when the person intends
to close the eye, and its converse. Dyskinesias,
such as tardive dyskinesia, are oral-buccal-lingual
masticatory movements of the face and choreoathetoid
movements of the limbs.
Stereotyped movements, such as head-banging,
rocking or repetitive hand movements, are apparently
intentional behaviors and are often rhythmic.
Compulsions, as in Obsessive Compulsive
Disorder, are differentiated from tics in that they are
intentional behaviors, whereas tics are involuntary.
The essential features of this disorder are multiple motor and
one or more vocal tics. These may appear simultaneously or at
different periods during the illness. The tics occur many times
a day, nearly every day or intermittently throughout a period of
more than one year. The anatomic 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 sounds such as clicks, grunts, yelps,
barks, sniffs and coughs or words. Coprolalia, a complex vocal
tic involving the uttering of obscenities, is present in up to a
third of cases. Complex motor tics involving touching, squatting,
deep knee bends, retracing steps and twirling when walking are
often present.
In approximately half the cases, the first symptoms to appear
are bouts of a single tic, the most frequently eye-blinking, less
frequently tics involving another part of the face or body.
Initial symptoms can also include tongue protrusion, squatting,
sniffing, hopping, skipping, throat-clearing, stuttering, uttering
sounds or words and coprolalia. Other cases begin with
multiple symptoms, which may include any combination of the
previously described tics and various noises such as barks,
grunts, screams, yelps or snorts.
Associated features. There may be other
symptoms, such as mental coprolalia (sudden, intrusive,
senseless thoughts of socially unacceptable or obscene words,
phrases or sentences that differ from true obsessions in that
no attempt is made to ignore, supress or neutralize the thoughts),
obsessions and compulsions.
In clinical samples, other mental disorders are frequently
associated with Tourette's Disorder, particularly
Attention-deficit Hyperactivity Disorder and Obsessive
Compulsive Disorder. It is not clear if this co-morbidity also
exists in representative community samples.
Age of onset. The median age at onset is 7
years and the great majority have an onset before age 14. The
disorder may appear as early as one year of age.
Course. The disorder is usually lifelong, though
periods of remission lasting from weeks to years may occur. In
some cases, the severity and frequency of the symptoms
diminish during adolescence and adulthood and the symptoms
do not vary in severity over time as much as before. In other
cases, the symptoms of the disorder disappear entirely,
usually by early adulthood.
Complications. Complications 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), skin problems
(from picking) and, in rare cases, self-mutilation (from
head-banging).
Prevalence. The estimated lifetime prevalence
rate is at least 0.5 per thousand.
Sex ratio. The disorder is at least three times
more common in males than in females.
Familial pattern. Tic Disorders are more
common among first-degree biologic relatives of people with
Tourette's Disorder than among the general population. Evidence
suggests that Tourette's Disorder and Chronic Motor or Vocal
Tic Disorder may be inherited as a single autosomal dominant
disorder.
In addition, there is some evidence that Obsessive Compulsive
Disorder is more common in first-degree biologic relatives of
people with Tourette's Disorder than in the general population
and is another expression of the same underlying disorder.
Differential diagnosis. See
differential diagnosis of tics.
Amphetamine Intoxication, many neuroligic disorders
(such as cerebrovascular accidents, Lesch-Nyhan syndrome,
Wilson's disease, Sydenham's chorea, Huntington's chorea
and multiple sclerosis), Organic Mental Disorders,
and Schizophrenia may present with
abnormal motor movements. These disorders can readily be
differentiated from Tourette's Disorder because they have
distinguishing symptoms, signs, clinical course and
physiologic abnormalities as revealed by laboratory tests and
none of them involve vocalizations similar to the clicks, grunts,
yelps, barks, sniffs, coughs and words of Tourette's Disorder.
307.23 Tourette's Disorder
| Diagnostic criteria for 307.23 Tourette's Disorder |
|
The essential features of this disorder are either motor or vocal tics, but not both (as in Tourette's Disorder). The other characteristics of the disorder are generally the same as Tourette's Disorder, except that the severity of the symptoms and the functional impairment are usually much less.
Familial pattern. Both Chronic Motor or Vocal Tic Disorder and Tourette's Disorder frequently occur in the same families and appear to be genetically related.
Differential diagnosis. In Transient Tic Disorder, the duration of the disturbance is always less than one year. In Tourette's Disorder there are both motor and vocal tics. A rare disorder of adolescence and adulthood, sometimes referred to as "psychogenic cough," or "chronic cough of adolescence," is distinguished from Chronic Motor or Vocal Tic Disorder by the monosymptomatic and intentional nature of the symptom.
| Diagnostic criteria for 307.22 Chronic Motor or Vocal Tic Disorder |
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The essential feature of this disorder is single or multiple motor and/or vocal tics that occur many times a day, nearly every day for at least two weeks, but for no longer than twelve consecutive months. (Thus, the diagnosis is not made if there is a history of Tourette's or Chronic Motor or Vocal Tic Disorder, both of which require a duration of at least one year.)
The most common tic is eye-blinking or another facial tic. However, the whole head, torso or limbs may be involved. In addition, there may be vocal tics. A person may have only one or a number of tics; if the latter, the tics may be performed simultaneously, sequentially or randomly.
Age of onset. Age at onset is always during childhood or early adolescence and may be as early as two years of age.
Course. The tics may disappear permanently, or recur, especially during periods of stress. In rare cases, after a period of partial remission, the person may develop either Tourette's Disorder or Chronic Motor or Vocal Tic Disorder.
Complications. No information.
Prevalence. Surveys of schoolchildren have reported that from 5% to 24% have had a history of some kind of tic. However, since these surveys do not specify a minimum or a maximum of duration, it is not known how applicable these findings are to the prevalence of Tic Disorders as defined in this manual.
Sex ratio. Most studies find the disorder three times more common in males than in females.
Familial pattern. Tic Disorders are apparently more common in first-degree biological relatives of people with Transient Tic Disorder than in the general population.
Differential diagnosis. In Tourette's Disorder and Chronic Motor or Vocal Tic Disorder, the duration of the disturbance is at least one year. See differential diagnosis of tics and Tourette's Disorder.
| Diagnostic criteria for 307.21 Transient Tic Disorder |
Specify: single episode or recurrent. |
Tics that do not meet the criteria for a specific Tic Disorder. An example is a Tic Disorder with onset in adulthood.