A tic is a sudden, rapid, recurrent, nonrhythmic motor movement or vocalization. In Tourette’s Disorder, an individual experiences both motor and vocal tics at some time during the illness, although not necessarily concurrently. The tics may wax and wane in frequency but must have persisted for more than 1 year since first tic onset, and onset must be before age 18 years. In Persistent (Chronic) Motor or Vocal Tic Disorder, single or multiple motor or vocal tics must have been present during the illness, but not both motor and vocal (because that would be Tourette’s Disorder). The tics may wax and wane in frequency but must have persisted for more than 1 year since first tic onset, and onset is before age 18 years. In Provisional Tic Disorder, single or multiple motor and/or vocal tics are present, and the tics must have been present for less than 1 year since first tic onset, and onset is before age 18 years. Last, criteria must have never been met for Tourette’s disorder or persistent (chronic) motor or vocal tic disorder.