There's no specific test that can diagnose Tourette syndrome. The diagnosis is based on the history of your signs and symptoms.

The criteria used to diagnose Tourette syndrome include:

  • Both motor tics and vocal tics are present, although not necessarily at the same time
  • Tics occur several times a day, nearly every day or intermittently, for more than a year
  • Tics begin before age 18
  • Tics aren't caused by medications, other substances or another medical condition

A diagnosis of Tourette syndrome might be overlooked because the signs can mimic other conditions. Eye blinking might be initially associated with vision problems, or sniffling attributed to allergies.

Both motor and vocal tics can be caused by conditions other than Tourette syndrome. To rule out other causes of tics, your doctor might recommend:

  • Blood tests
  • Imaging studies such as MRI