Tics are rapid, repeated, involuntary contractions of a group of muscles that either result in a movement (a motor tic) or a sound (a vocal tic). Most tics are mild, infrequent and hardly noticeable, but some can be frequent and severe.
Motor tics can affect any part of the body, but often involve the muscles of the face, eyes, head and neck, producing movements such as:
- facial twitching,
- grimacing,
- blinking, and
- shrugging of the shoulders.
Common vocal tics include:
- coughing,
- grunting, or
- clearing the throat.
Sometimes tics may appear to be similar to normal movements. However, tics are not voluntary and most people are unable to consciously control them. Some people are able to suppress tics for a short time, although this is said to be like holding back a sneeze. The person feels increasing tension until the tic is finally released.
Types of tic
Tics can be classified into three categories according to the type of tic and how long the person has had it for. The three categories of tics are described below.
Transient tic disorders
Transient tic disorders occur when a person has a motor tic, a vocal tic or both almost every day for at least four weeks, but not for more than a year.
Transient motor tics, such as blinking or snapping the fingers, usually only affect one muscle group.
Transient tics are very common, with about one in 10 children developing one or more tics during their school years. Transient tics are not harmful. They do not usually require treatment and usually disappear as the child gets older.
Chronic tic disorders
Chronic tic disorders occur when a person has had either a motor tic or a vocal tic (but not both), regularly or intermittently for more than one year. During this time, they will not have had a tic-free period for more than three months.
Although chronic tics do not usually require treatment, they can cause problems. For example, a child with a chronic tic may be ridiculed or bullied by other children.
Tourette’s syndrome
Tourette’s syndrome (TS) is a condition that includes behavioural problems, such as attention deficit hyperactivity disorder (ADHD) and obsessive compulsive disorder (OCD).
People with TS also usually have chronic tic disorders, involving severe, multiple tics that include at least one vocal tic and several motor tics.
A person with TS will experience both motor tics and vocal tics on a regular basis or intermittently for more than one year. During this time, they will not have had a tic-free period for more than three months.
See Useful links for more information about Tourette’s syndrome.
How common are tics?
Tics are more common in boys than in girls.
Transient tic disorders are very common. Many children develop them while they are at school, usually from seven to nine years of age.
Compared with transient tic disorders, chronic tic disorders and Tourette’s syndrome are rare and often continue into adulthood.
