Persistent (Chronic) Motor or Vocal Tic Disorder

marijuana, and deep brain stimulation have been successfully tried in some cases.

A person gradually transitions from provisional tic disorder to chronic motor or vocal tic

disorder if they have symptoms lasting many times a day nearly every day for a period of

greater than 1 year. In addition, there cannot be a tic-free period longer than three months.

The patient will have at least one motor tic or at least one vocal tic but cannot have both motor

and vocal tics. The onset of the disease is prior to 18 years and cannot be due to encephalitis,

stimulants, or Huntington’s disease. The patient also can never have carried the diagnosis of

Tourette syndrome if diagnosed with chronic motor or vocal tic disorder.