TIC
DISORDERS
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 suppressed for
varying lengths of time. All forms of tics
are often 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,
neckjerking, 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.
Dyskinesas, such as tardive dyskinesia, are
oral-buccal-lingual masticatory movements of
the face arid 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.
Tourette's
Disorder
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,
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. 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, suppress, 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 at 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.
Amphetamine Intoxication, many neuralgic
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.
Diagnostic Criteria for
Tourette’s Disorder
A. Both multiple motor and
one or more vocal tics have been present at
some time during the illness, although not
necessarily concurrently.
B. The tics occur many times
a day (usually in bouts), nearly every day or
intermittently throughout a period of more
than one year.
C. The anatomic location,
number, frequency, complexity, and severity
of the tics change over time.
D. Onset before age 21.
F. Occurrence not
exclusively during Psychoactive Substance
Intoxication or known central nervous system
disease, such as Huntington's chorea and
postviral encephalitis.
Chronic
Motor or Vocal Tic 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 Chronic
Motor or Vocal Tic Disorder
A. Either motor or vocal
tics, but not both, have been present at some
time during the illness.
B. The tics occur many times
a day, nearly every day, or intermittently
throughout a period of more than one year.
C. Onset before age 21.
D. Occurrence not
exclusively during Psychoactive Substance
Intoxication or known central nervous system
disease, such as Huntington's chorea and
postviral encephalitis.
Transient
Tic Disorder
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 at 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 duration, it is not
known how applicable these findings are to
the prevalence of Tic Disorders.
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.
Diagnostic Criteria for Transient
Tic Disorder
A. Single or multiple motor
and/or vocal tics.
B. The tics occur many times
a day, nearly every day for at least two
weeks, but for no longer than twelve
consecutive months.
C. No history of Tourette's
or Chronic Motor or Vocal Tic Disorder.
D. Onset before age 21.
E. Occurrence not
exclusively during Psychoactive Substance
Intoxication or known central nervous system
disease, such as Huntington's chorea and
postviral encephalitis.
Tic Disorder Not Otherwise
Specified
Tics that do not meet the criteria for a
specific Tic Disorder. An example is a Tic
Disorder with onset in adulthood.
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