Tests and diagnosisBy Mayo Clinic staff
There's no specific test that can diagnose Tourette syndrome. Instead, doctors must rely on the history of symptoms to diagnose the disorder.
The Diagnostic and Statistical Manual of Mental Disorders (DSM) determines the criteria for a diagnosis of Tourette syndrome. Published by the American Psychiatric Association, the DSM is used by mental health professionals to diagnose certain conditions and by insurance companies to reimburse for treatment.
The criteria to diagnose Tourette syndrome include these:
- Both motor tics and vocal tics must be present, although not necessarily at the same time.
- Tics occur several times a day, nearly every day or intermittently, for more than a year. There must not be a break in tics for more than a three-month period.
- The onset of tics occurs before age 18.
- Tics aren't caused by medications, other substances or another medical condition.
Diagnosis of Tourette syndrome may be delayed because families and even doctors are sometimes unfamiliar with the symptoms, or the symptoms may mimic other problems. Eye blinking may be initially associated with vision problems, for instance, while sniffling may be attributed to allergies.
Because other serious health conditions can cause motor or vocal tics, your doctor may suggest having tests to rule out other causes. These tests include blood tests or neuroimaging studies, such as magnetic resonance imaging (MRI).
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