How is Tourette syndrome (TS) diagnosed?

Only a doctor can diagnose tic disorders and Tourette's syndrome. Tourette syndrome (TS) usually appears between the ages of 5 and 18 with mild tics of the face, head, or arms. Over time, the tics can become more involved, frequent, and disruptive. In about a third of people diagnosed in childhood symptoms, the symptoms spontaneously resolve as they reach adulthood. In another a third of patients, symptoms are substantially reduced during adulthood; the remainder of patients have symptoms throughout adulthood. Patients with tic disorders frequently have associated psychiatric symptoms such as obsessive-compulsive disorder, attention deficit disorder, anxiety, and phobias.

Tourette syndrome (TS) is a diagnosis that doctors make after verifying that the patient has had both motor and vocal tics for at least one year. The existence of other neurological or psychiatric conditions like childhood-onset involuntary movement disorders, such as dystonia; or psychiatric disorders characterized by repetitive behaviors/movements (for example, stereotypic behaviors in autism and compulsive behaviors in obsessive-compulsive disorder-OCD), can also help doctors arrive at a diagnosis. Common tics are diagnosed easily by knowledgeable clinicians. However, atypical symptoms or presentation (for example, onset of symptoms in adulthood) may require specific specialty expertise for diagnosis. There are no blood or laboratory tests needed for diagnosis, but neuroimaging studies, such as magnetic resonance imaging (MRI), computerized tomography (CT), and electroencephalogram (EEG) scans, or certain blood tests may be used to rule out other conditions that might be confused with TS.

Patients usually obtain a formal diagnosis of TS only after symptoms have been present for some time. The reasons for this are many. For families and physicians unfamiliar with TS, mild and even moderate tic symptoms may be considered inconsequential, a part of a developmental phase, or the result of another condition. For example, parents may think that eye blinking is related to vision problems or that sniffing is related to seasonal allergies. Many patients are self-diagnosed after they, their parents, other relatives, or friends read or hear about TS from others.

This information is based on source information from the National Institute of Neurological Disorders and Stroke.

The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) is used by health professionals to help diagnose tic disorders such as Tourette syndrome (TS). Tics are sudden twitches, movements or sounds that people do repeatedly. People who have tics cannot stop their body from doing these things. For a person to be diagnosed with TS, he or she must:

  1. have both multiple motor tics (for example, blinking or shrugging the shoulders) and at least one vocal tics (for example, humming, clearing the throat, or yelling out a word or phrase), although they might not always happen at the same time;
  2. have had tics for at least a year. The tics can occur many times a day (usually in bouts) nearly every day, or off and on;
  3. have tics that begin before he or she is 18 years of age;
  4. have symptoms that are not due to taking medicine or other drugs or due to having another medical condition (for example, seizures, Huntington disease or postviral encephalitis).

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