Tic disorders, which include Tourette's Syndrome, Chronic Tic Disorder, and Provisional Tic Disorder, are characterized by involuntary movements and sounds that are done repeatedly. The three Tic Disorders are set apart by the type of tics that a person demonstrates (motor, vocal, or both) and by the length of time the tics have been present. Someone with Tourette's Disorder has at least two motor tics and at least one vocal tic in some combination for more than a year.
Tics can be either simple or complex. Simple tics occur very briefly (milliseconds); complex tics can last for seconds. Examples of simple motor tics include eye blinking, shoulder shrugging, arm jerking, facial scrunching, and head turning. Complex motor tics involve coordinated patterns of movements and several muscle groups; these movements tend to be slower and can seem purposeful, such as sniffing or touching objects or hopping, jumping, or twirling. Simple vocal tics include throat clearing, hooting and shouting. Complex vocal tics are words or phrases that may or may not be recognizable but that always occur out of context and, rarely, may be inappropriate (ex: swearing). People who have tics cannot stop their bodies or voices from doing these things; they may be able to keep themselves from doing a certain tic for a period of time, but it is difficult and ultimately the person has to let the tic out.
Tics come and go - they are magnified when the individual is anxious, excited, or exhausted and diminished during periods of calm. They wax and wane in severity; and the specific motor or vocal tics that a person demonstrates can change over time. The onset of tics us usually between 4 and 6 years of age, with a peak in severity between the ages of 10 and 12.