A tic is a sudden, reoccurring motor movement that is beyond a person's control. The tic can involve as little as one muscle, to several muscles at the same time. A common tic that many of us have experienced from time to time, is a twitching of the eye. Other tics include eye blinking, shoulder shrugging, face grimacing, jerking, grunting, clearing the throat, or nose wrinkling. These are called simple motor tics.

Tics of more complex nature include jumping, touching, bending, twirling, or moving into a strange body position. A tic can also be verbal, such as swearing, making an obscene statement, or calling someone a name.

Tics can last from several seconds to several hours and can be involuntary or voluntary. They are typically experienced as a mounting tension or bodily need, such as a persistent need to scratch an itch. Only when the individual performs the tick, is tension and anxiety released within the individual with a tic disorder.