Tic

A tic is a sudden body movement that a person can't control. It might be a jerking movement of the hand, or blinking a lot, or a throat sound. Even if the person is told that they are doing it, they usually can't stop. Sometimes if they try really hard, they can make the tic go away for a little bit, but they can't make it go away all the time. It's kind of like when you have something in your throat, eventually you just have to cough.

Different kinds of tic, as they occur in patients with Tourette's syndrome

Tics can be either "motor tics" or "phonic tics." If they are "motor tics" it means they're movements, like blinking or shrugging shoulders. If they are "phonic tics" it means they're sounds, like clearing your throat, sniffing, or yelling.

Tics are common in childhood, four to twelve percent of all children have tics. Very often this is transitory, tics rarely last longer than six months. Boys have tics more often than girls. About three times more boys than girls have tics. Sometimes, people can have a "tic" in the family, meaning that more than one member has a tic, or that a parent used to have a tic.

Some tics can be treated, usually with behaviour therapy. In cases where the tic is difficult to treat, antipsychotics are sometimes used.

• Tics are part of the obsessive-compulsive complex of behavioural disorders,