Tic Disorders

What are tics?

Tics are sudden, rapid, recurrent, nonrhythmic motor movements or vocalizations. An individual may have various tic symptoms over time, but at any point in time, the tic repertoire recurs in a characteristic fashion. Although tics can include almost any muscle group or vocalization, certain tic symptoms, such as eye blinking or throat clearing, are common across patient populations. Tics are generally experienced as involuntary but can be voluntarily suppressed for varying lengths of time.

Tic disorders have 4 diagnostic categories:

  1. Tourette’s disorder
  2. Persistent (chronic) motor or vocal tic disorder
  3. Provisional tic disorder
  4. Other specified and unspecified tic disorders
The tic disorders are hierarchical in order (i.e., Tourette’s disorder, followed by persistent [chronic] motor or vocal tic disorder, followed by provisional tic disorder, followed by the other specified and unspecified tic disorders), such that once a tic disorder at one level of the hierarchy is diagnosed, a lower hierarchy diagnosis cannot be made (Criterion E).
Simple and Complex Tics

Tics can be either simple or complex:

  • Simple motor tics are of short duration (i.e., milliseconds) and can include eye blinking, shoulder shrugging, and extension of the extremities.
  • Simple vocal tics include throat clearing, sniffing, and grunting often caused by contraction of the diaphragm or muscles of the oropharynx.
  • Complex motor tics are of longer duration (i.e., seconds) and often include a combination of simple tics such as simultaneous head turning and shoulder shrugging.
  • Complex tics can appear purposeful, such as a tic-like sexual or obscene gesture (copropraxia) or a tic-like imitation of someone.

Comparison of Tic disorders

Comparison

Tourette's Persistent Motor or Vocal Tic Disorder Provisional Tic Disorder
Tics Multiple motor AND at least 1 vocal Motor OR Verbal Motor AND/OR Verbal
Length > 1 year > 1 year < 1 year
Age of onset Before age 18 Before age 18 Before age 18

Tourette’s Disorder

Criterion A

Both multiple motor and one or more vocal tics have been present at sometime during the illness, although not necessarily concurrently.

Criterion B

The tics may wax and wane in frequency but have persisted for more than 1 year since first tic onset.

Criterion C

Onset is before age 18 years.

Criterion D

The disturbance is not attributable to the physiological effects of a substance (e.g.,cocaine) or another medical condition (e.g., Huntington’s disease, post-viral encephalitis).

Persistent (Chronic) Motor or Vocal Tic Disorder

Criterion A

Single or multiple motor or vocal tics have been present during the illness, but not both motor and vocal.

Criterion B

The tics may wax and wane in frequency but have persisted for more than 1 year since first tic onset.

Criterion C

Onset is before age 18 years.

Criterion D

The disturbance is not attributable to the physiological effects of a substance (e.g.,cocaine) or another medical condition (e.g., Huntington’s disease, post-viral encephalitis).

Criterion E

Criteria have never been met for Tourette’s disorder. Specify if: With motor tics only With vocal tics only

Provisional Tic Disorder

Criterion A

Single or multiple motor and/or vocal tics.

Criterion B

The tics have been present for less than 1 year since first tic onset.

Criterion C

Onset is before age 18 years.

Criterion D

The disturbance is not attributable to the physiological effects of a substance (e.g.,cocaine) or another medical condition (e.g., Huntington’s disease, post-viral encephalitis).

Criterion E

Criteria have never been met for Tourette’s disorder or persistent (chronic) motor or vocal tic disorder.

  • Give 0.05 mg of clonidine PO once daily as a starting dose
  • Titrate to 0.15 to 0.3mg PO once daily