The exact cause of tics and Tourette syndrome is unknown, but it may involve a combination of genetic, developmental and neurological factors. Some possible causes and risk factors are:

• A family history of tics or Tourette syndrome increases the risk of inheriting the condition.
• Having mutations in certain genes that affect brain development and function may play a role. Such as Down’s, Fragile X, XY, and others
• Abnormalities or imbalances in brain chemicals called neurotransmitters, such as glutamate, serotonin, and dopamine, may affect nerve cell communication and cause tics.
• Other causes: Head trauma, drugs (cocaine, neuroleptics), neurodegenerative disorder (HD), autism, encephalitis, infections (HIV)

• Tics and Tourette syndrome are diagnosed based on the history of signs and symptoms, without any specific tests. 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 are not caused by medications, other substances or another medical condition

  Your neurologist may also request some tests (such as blood tests, CT scan or MRI) to rule out other possible causes of tics.