History
Tics tend to fluctuate in severity, distribution, and character over intervals that are usually of weeks to years. A typical example is as follows: A boy starts blinking excessively when aged 5 years and develops a repetitive nonrhythmic palatal click several months later. By age 7 years, the blinking persists, while forceful nasal exhalations and shoulder shrugging have replaced the click. As a teenager, he has all the old tics present together with violent head shaking. In college, subtle head shaking and hardly visible abdominal tensing may be the only remaining tics, with exacerbations during examination week. [139]
Two case definitions for TS are accepted widely: the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) definition from the American Psychiatric Association, 2013, [1] which is widely used in the United States for clinical purposes (see the DSM-5 criteria for tic disorders below); and the Tourette Syndrome Study Group (TSSG) definition, 1993 [2] (see TSSG criteria for tic disorders below). Experts identify similar groups of patients by using either set of criteria.
American Psychiatric Association criteria for tic disorders
Diagnostic criteria for Tourette syndrome (DSM-5 307.23) are as follows:
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Both multiple motor and 1 or more vocal tics have been present at some time during the illness, though not necessarily concurrently. (A tic is a sudden, rapid, recurrent, nonrhythmic, stereotyped motor movement or vocalization)
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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
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The onset is before age 18 years
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The disturbance is not due to the direct physiologic effects of a substance (eg, stimulants) or a general medical condition (eg, Huntington disease or postviral encephalitis)
Diagnostic criteria for chronic motor or vocal tic disorder (DSM-5 307.22) are as follows:
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Single or multiple motor or vocal tics (eg, sudden, rapid, recurrent, nonrhythmic, stereotyped motor movement or vocalizations), but not both, have been present at some time during the illness
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The tics occur many times a day 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
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The onset is before age 18 years
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The disturbance is not due to the direct physiologic effects of a substance (eg, stimulants) or a general medical condition (eg, Huntington disease or postviral encephalitis).
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Criteria have never been met for TS
Diagnostic criteria for transient tic disorder (DSM-5 307.21) are as follows:
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Single or multiple motor and/or vocal tics (eg, sudden, rapid, recurrent, nonrhythmic, stereotyped motor movement or vocalizations) are present
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The tics occur many times a day, nearly every day for at least 4 weeks, but for no longer than 12 consecutive months
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The onset is before age 18 years
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The disturbance is not due to the direct physiologic effects of a substance (eg, stimulants) or a general medical condition (eg, Huntington disease or postviral encephalitis)
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Criteria have never been met for TS or chronic motor or vocal tic disorder
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Specify if this is a single or recurrent episode
Tic disorder not otherwise specified (DSM-5 307.20): This category is for disorders characterized by tics that do not meet criteria for a specific tic disorder. Examples include tics lasting less than 4 weeks or tics with an onset after age 18 years.
Tourette Syndrome Study Group criteria for tic disorders
Diagnostic criteria for TS (coded as A-1 or A-2 depending on source of information) are as follows:
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Both multiple motor and one or more vocal tics have been present at some time during the illness, though not necessarily concurrently
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The tics occur many times a day, nearly every day, or intermittently throughout a period of more than 1 year
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The anatomic location, number, frequency, complexity, type, or severity of tics changes over time
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Tics have their onset before age 21 years
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Involuntary movements and noises cannot be explained by other medical conditions
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Motor and/or vocal tics must be witnessed by a reliable examiner directly at some point in the illness or be recorded by videotape or cinematography (for definite TS, A-1) or (for tics not witnessed by a reliable examiner) tics must be witnessed by a reliable family member or close friend, and description of tics as demonstrated must be accepted by reliable examiner (for TS by history, A-2)
Diagnostic criteria for chronic multiple motor tic or phonic tic disorder (B-1 and B-2) are as follows:
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Either multiple motor or vocal tics, but not both, have been present at some time during the illness
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The tics occur many times a day, nearly every day, or intermittently throughout a period of more than 1 year
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The anatomic location, number, frequency, complexity, or severity of tics changes over time
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Tics have their onset before age 21 years
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Involuntary movements and noises cannot be explained by other medical conditions
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Motor and/or vocal tics must be witnessed by a reliable examiner directly at some point in the illness or be recorded by videotape or cinematography (for definite chronic multiple motor tic or phonic tic disorder, B-1) or (for tics not witnessed by a reliable examiner) tics must be witnessed by a reliable family member or close friend, and description of tics as demonstrated must be accepted by a reliable examiner (for chronic multiple motor tic or phonic tic disorder by history, B-2)
Diagnostic criteria for chronic single tic disorder (C-1 and C-2): This disorder is the same as in the previous category (B-1 and B-2), but with a single motor or vocal tic.
Diagnostic criteria for transient tic disorder (D-1 and D-2) are as follows:
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This disorder is characterized by single or multiple motor and/or vocal tics
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The tics occur many times a day, nearly every day, for at least 2 weeks, but for no longer than 12 consecutive months, although the disorder began over 1 year ago
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The anatomic location, number, frequency, complexity, or severity of tics changes over time
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The patient has no history of TS or chronic motor or vocal tic disorders
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Tics have their onset before age 21 years
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Motor and/or vocal tics must be witnessed by a reliable examiner directly at some point in the illness or be recorded by videotape or cinematography (definite transient tic disorder, D-1) or (for tics not witnessed by a reliable examiner) tics must be witnessed by a reliable family member or close friend, and description of tics as demonstrated must be accepted by a reliable examiner (for transient tic disorder by history, D-2)
Diagnostic criteria for nonspecific tic disorder (E-1 and E-2) are as follows:
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Tics that do not meet the criteria for a specific tic disorder fall into this category; an example would be a tic disorder with tics lasting less than 1 year and without any change over that period of time
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Motor and/or vocal tics must be witnessed by a reliable examiner directly at some point in the illness or by videotape or cinematography (for definite nonspecific tic disorder, E-1) or (for tics not witnessed by a reliable examiner) tics must be witnessed by a reliable family member or close friend, and description of tics as demonstrated must be accepted by a reliable examiner (for nonspecific tic disorder by history, E-2)
Diagnostic criteria for definite tic disorder, diagnosis deferred F: This disorder meets all criteria for definite TS (first definition, A1), but duration of illness has not yet extended to 1 year.
Diagnostic criteria for probable TS type G are as follows:
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Type 1 fulfills all criteria for definite TS (first definition, A1) except for the third and fourth criteria
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Type 2 fulfills all criteria for definite TS (first definition, A1) except for the first criterion; this type can be either a single motor tic with vocal tics, or multiple motor tics with possible vocal tic(s)
Diagnostic criteria for probable multiple tic disorder, or motor and/or vocal tics type H: This disorder fulfills all criteria for definite chronic multiple tic disorder (second definition) completely, except for the third and/or fourth criteria.
Physical Examination
An important caveat is that many patients with tics may not demonstrate them on their first office visit, especially when the examiner is looking directly at the patient. In such cases, important aids to diagnosis can include obtaining the patient's history from several sources; scheduling follow-up office visits; and, most importantly, assigning the patient (or his or her parents) to bring a home video to show their behavior. Learning to watch the patient out of the corner of one's eye while speaking with a family member or writing in the chart is also helpful.
The remainder of the physical examination is important primarily for differential diagnosis. Special attention should be paid to the patient's mental status, cornea (Kayser-Fleischer rings), eye movements, abnormal movements, muscle tone, gait, postural stability, and bradykinesia or tremor if any. General neurological and psychiatric examinations are also important.
A number of non-tic symptoms are relatively common in patients with TS and are described briefly in the Table below.
Table. Symptoms of TS (Open Table in a new window)
Symptom |
Description/Comment |
Sensory hypersensitivity |
Cannot stand to have wrinkly socks, cuts the tags off his or her shirts, refuses all but bland food, or becomes agitated in a visually complex environment |
Learning disability |
Approximately 20% in clinical samples, more closely associated with comorbid ADHD than with tics; also associated with male sex, earlier onset, severity, perinatal problems, and lower rates in family members [140] |
School phobia |
Can be an adverse effect of neuroleptic treatment |
Complex socially inappropriate behavior |
Insults, racial slurs, and paraphilias (or, more commonly, suppressed urges) are present in a large minority of patients with TS, associated with comorbid ADHD |
Rage attacks |
Sudden outbursts lasting approximately 5-30 min, usually in children or teenagers; inconsolable, unremitting violent frustration, commonly after being denied an unreasonable request; often followed by apparently sincere contrition and remorse |
Insistence on sameness |
Refusal to take a different route home or omit a step in a routine, even when hurried; often without a clear obsession or other obsessive-compulsive symptoms |
Anxiety and depression |
Common in patient samples but not clearly more common in the general TS population |
TS with both OCD and episodes of mania |
Surprisingly high rates of mania in patients with TS and OCD shown in at least 2 studies, management frequently difficult |
ADHD = attention deficit hyperactivity disorder; OCD = obsessive-compulsive disorder. |
Described below are the classification of tics, their general features, and the signs and symptoms of specific tics (sensory tics, dystonic tics, and coprolalia) and of related conditions such as OCD and ADHD.
Classification of tics
Tics are traditionally (if arbitrarily) classified by their distribution and complexity. Tics most often occur in the face, neck, pharynx, shoulders, and midline torso but can affect nearly any body part (see the image below).

Albin has pointed out that stimulation of the ventral basal ganglia can reproduce some socially meaningful complex gestures (eg, stereotyped fear or pleasure displays in rodents), and that socially meaningful gestures predominantly involve these same body regions. [141] However, some tics do not readily fit traditional classifications.
General features of tics
Most tics are simple, meaningless movements. Tics are not entirely random, however, often involving elements of experience, practice, and social convention.
Echolalia or echopraxia (ie, imitation of another's speech or movements) occurs in as many as one third of patients. Seeing another person with tics with excessive blinking may induce a bout of blinking in someone who has not had that tic for years. Similarly, hearing about tics increases their severity.
Tics sometimes appear to recapitulate a new, voluntary behavior. One example is "air typing" as a complex tic after learning to touch type (observed in 2 unrelated individuals by one of the authors).
A man whose self-history was published in 1902 described his tics as often involving an urge to do just what was forbidden, such as "clucking" when told to be quiet in school. He compared his motor and vocal tics to a "desire for forbidden fruit". [142] Complex tics can include inappropriate activities such as touching a hot iron or a stranger's breasts.
As with most movement disorders, tics are worse at times of emotional stress and are diminished dramatically during sleep.
Differentiation of tics from other movement disorders
Tics are distinguished from other movement disorders by several typical characteristics. First, tics are most commonly brief movements, yet not so brief as the movements of myoclonus.
Myoclonus is not suppressible, whereas tics (and chorea) are suppressible. Often, after prolonged forced suppression, a rebound of tic severity occurs, though this is hard to demonstrate in controlled settings. [143] Similarly, tics tend to improve somewhat when the individual is absorbed in an enjoyable or demanding activity.
Individual tics may resemble the individual movements of chorea, yet tics are repeated stereotyped movements, while chorea consists of movements that are unpredictably distributed through the body. For example, a man with tics may be "the guy who shakes his head," while someone with chorea may be simply "the guy that twitches a lot." However, in distinction to tremor or most stereotypies, including typical tardive dyskinesia, tics are not rhythmic.
The volition of tics
Tics are nearly unique compared with other movement disorders in the perceived degree of volition. Although tics are clearly not voluntary in the usual sense (no one decides to have tics), the term involuntary is not strictly accurate.
Often in children and occasionally in adults, tics appear to be truly involuntary: The person tics without awareness or without a sense of voluntary movement. However, when pressed for details, adults describe most tics as a volitional response to an irresistible impulse, rather than an involuntary movement. [144] For example, patients often say, "I shake my head" rather than "my head shakes."
One of the authors' patients tried to describe his tics to people who have not experienced them: "Think of the last time you were at the symphony or at church and you had a tickle in your throat. Maybe you could hold it back until the end of the quiet movement or the end of the prayer, but then you just had to cough or clear your throat. This is something like what it feels like to have a tic, but with TS it is happening throughout the day, every day."
Tic syndromes can nearly always be differentiated from uncomplicated OCD. Simple tics or pure obsessions are easily identified, and essentially all patients with chronic tics have simple tics at some point. However, because the definitions overlap, individual complex actions cannot always be labeled clearly as a tic rather than a compulsion.
Complex tics are generally preceded by sensory phenomena or occur without warning, whereas compulsions generally involve obsessive worries and themes of contamination or guilt. However, both can be associated with symmetry concerns or a need to repeat something until an ineffable sense of "getting it just right" is achieved. [145, 146]
Sensory tics
Sensory tics refer to repeated, unwanted, uncomfortable sensations, often in the absence of a verifiable stimulus. [147, 148] Common examples are "something in the throat," or a hard-to-describe local discomfort in the shoulders.
Sensory tics often precede motor or vocal tics but can occur independent of externally apparent tics. In the former case, they also are called premonitory sensations, and often the actual movement or vocalization is perceived as relieving the uncomfortable sensation, akin to "scratching the itch." Blinking after an uncomfortable sensation in the eye is one example. At other times, patients report a more generalized discomfort or restlessness, sometimes reminiscent of the subjective component of akathisia.
Some published self-descriptions of tics identify these sensory phenomena as the core symptoms of TS. [149] However, developmentally, children have motor tics several years (on average) before they first report premonitory sensations.
Not surprisingly, the distribution of sensory tics mimics that of motor and vocal tics.
Dystonic tics
Dystonic tics refer to repeated movements that resemble fragments of childhood-onset generalized dystonia. An example is one of the authors' patients, a man with lifelong mild motor and vocal tics who when 45 years old developed typical blepharospasm (involuntary squeezing of the eyelids). After 2 years, the blepharospasm remitted while other tics predominated, only to recur after a year or so.
This name also has been used to describe simpler nonclonic tics that alternatively, perhaps more aptly, have been called tonic tics. These are common, and examples include 1- to 5-second isometric contractions at the shoulders or repeated tensing of the abdominal muscles.
Coprolalia
Coprolalia refers to unprovoked, unwanted outbursts of obscenities and occurs in 10-40% of patients with TS, depending on the method of ascertainment. Many observers find coprolalia to be uncommon, occurring in fewer than 10% of patients.
A well-known case history describes a woman with coprolalia, among other tics, who became deaf in childhood. [150] She learned sign language and could communicate without tics until becoming fluent, whereupon she developed signing tics, including socially unacceptable signs. Signing tics also occur in prelingually deaf individuals. [151]
Obsessive-compulsive symptoms
Obsessions are unwanted repetitive thoughts, fears, or mental images, eg, "I better do that over again until it looks right." Compulsions are actions, generally perceived as volitional but irresistible, performed repeatedly to reduce obsessive worries or according to rigid rules. Common compulsions are counting, checking, straightening, hoarding, or grooming. Phenomenologically, obsessions and compulsions share many features with tics, and historically, some authors have referred to them as mental tics or psychic tics.
Obsessions and compulsions occur in tic patients about 20 times more commonly than in the general population. In many cases, symptoms meet DSM-IV criteria for OCD. Relatives also have markedly elevated rates of obsessions and compulsions, with or without tics. Conversely, relatives of children with OCD have high rates of TS whether or not the proband has TS. [152, 153] These facts support the view that obsessive-compulsive symptoms, like tics, are part of the natural TS phenotype rather than a comorbid second illness. [154, 108]
Findings such as those just described may suggest useful avenues for research into the treatment of tics. On the other hand, the observation that purely symptomatic therapies may treat 1 symptom but not the other makes sense if one accepts that they may be generated by different, but similarly affected, areas of the brain.
Attention deficit–hyperactivity disorder symptoms
Attention deficit–hyperactivity disorder (ADHD refers to a clinically defined syndrome beginning in childhood and characterized by inattention and distractibility, behavioral hyperactivity, or marked impulsivity.
In recent years, several important findings have emerged from studies of (nontic) ADHD. The reliability of ADHD diagnosis by experts compares well with that of most other medical illnesses.
Findings suggest that, like essential hypertension, ADHD as currently defined represents a clinically convenient threshold imposed on a unimodal population distribution of symptom severity. The syndrome is highly heritable whether the phenotype is defined by clinician diagnoses or parents' reports of symptoms. Finally, safe treatments of proven efficacy are available.
Clearly, ADHD is common in patients with TS seen by physicians. A Centers for Disease Control and Prevention (CDC) survey, 64% of TS patients had also been diagnosed with ADHD. To some extent, the prevalence may represent primarily referral bias; patients with uncomplicated tics are less likely to seek medical attention. However, ADHD is common even in epidemiologic samples of TS and in TS-affected relatives of pure-TS probands.
The genetic relationship of TS with ADHD is less clear than its relationship with OCD. [108] The clinical picture is similar to that observed in populations without tics.
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Tourette syndrome and other tic disorders. Schematic of the hypothetical reorganization of the basal ganglia output in tic disorders, with excitatory projections (open arrows) and inhibitory projections (solid arrows). Line thickness represents the relative magnitude of activity. When a discrete set of striatal neurons becomes active inappropriately (right), aberrant inhibition of a discrete set of internal segment of globus pallidus (GPi) neurons occurs. The abnormally inhibited GPi neurons disinhibit thalamocortical mechanisms involved in a specific unwanted competing motor pattern, resulting in a stereotyped involuntary movement.
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Tourette syndrome and other tic disorders. Segregated anatomy of the frontal-subcortical circuits: dorsolateral (blue), lateral orbitofrontal (green), and anterior cingulate (red) circuits in the striatum (top), pallidum (center), and mediodorsal thalamus (bottom).
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Tourette syndrome and other tic disorders. Graphic shows the relative likelihood of lifetime sensory tics in a given region, as based on self-report of patients with Tourette syndrome. Overt tics are distributed similarly.
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Tourette syndrome and other tic disorders. Immunologic response found in patients with Sydenham chorea is also found in patients with Tourette syndrome and obsessive-compulsive disorder. Points on the graph represent percent expression of D8/17 antigen on circulating B lymphocytes.
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Tourette syndrome and other tic disorders. In a randomized controlled trial of habit reversal therapy (HRT), results differed significantly from those of a control therapy (massed practice; P < .001, analysis of variance). The HRT group had a 97% reduction in tics at 18-month follow-up, with 80% of patients tic-free.