Tic disorders

Tic disorders are defined in the Diagnostic and Statistical Manual of Mental Disorders (DSM) based on type and duration of tics, as follows:
 * Transient tic disorder consists of multiple motor and/or phonic tics with duration of less than 12 months.
 * Chronic tic disorder is either single or multiple motor or phonic tics, but not both, which are present for more than a year.
 * Tourette's disorder is diagnosed when both motor and phonic tics are present for more than a year.
 * Tic Disorder NOS is diagnosed when tics are present, but do not meet the criteria for any specific tic disorder.

DSM-IV-TR diagnosis codes for the tic disorders are:
 * 307.20 Tic Disorder NOS (Not Otherwise Specified)
 * 307.21 Transient Tic Disorder
 * 307.22 Chronic Motor or Vocal Tic Disorder
 * 307.23 Tourette's Disorder

ICD10 diagnosis codes are: Tourette syndrome is the more severe expression of a spectrum of tic disorders, which are thought to be due to the same genetic vulnerability. Nevertheless, most cases of Tourette syndrome are not severe. Although a good body of investigative work indicates genetic linkage of the various tic disorders, further study is needed to confirm the relationship. (Swerdlow, 2005 and Black)
 * F95.0  Transient tic disorder
 * F95.1  Chronic motor or vocal tic disorder
 * F95.2  Combined vocal and multiple motor tic disorder [de la Tourette]
 * F95.8  Other tic disorders
 * F95.9  Tic disorder, unspecified