Tics are a type of abnormal movement or behavior characterized by being both involuntary and yet partially controllable. People who experience tics perform them without conscious intent but have the ability to suppress them to some extent with concentrated mental effort. A premonitory urge to perform the movement or behavior often precedes the tic. This urge may be perceived by the person as a sensation in the affected body part, such as tension or pressure, or it may be an emotion, such as anxiety or fear. In either case, performing the tic relieves the urge. If the tic is consciously suppressed, however, the premonitory symptom will increase in intensity, causing the person psychological discomfort. Tic symptoms wax and wane over the course of time, with ...