Tics

An Introduction

Tics are abnormal movements or behaviors that are preceded by an irresistible urge. These movements are repetitive and sudden. A tic can be consciously repressed momentarily, but like a sneeze or a cough, eventually must be acted on. In this way, a tic is not something that is under the control of the afflicted person.

Tics can be displayed in a variety of different ways. They are almost always quick and jerky in nature.

They can be physical, like a twitching eyebrow, or vocal, like a barking sound. Prolonged behavior like singing, on the other hand, is unlikely to be a tic.

Other examples of tics include throat clearing, clicking or hissing noises, or sniffing. Sometimes words can be pronounced as part of a tic, including swear words (coprolalia), although this is uncommon. Movements can include clenching fists, arm jerking, shoulder shrugging, sticking out the tongue, and more.

Many people with tics find them embarrassing, and may try to hide the tic in some way. For example, a schoolgirl might drop her pencil in order to crawl briefly under her desk and perform the tic. Other tics might be camouflaged as more acceptable behavior, like pretending to have a cough in order to make a throat clearing sound.

Who Gets Tics?

Tics are often a disorder of childhood. They are very common. According to some reports, about 20% of children have tics at some time.

More boys experience tics than girls. The usual age of onset is between the ages of 7 to 10, but tics can start earlier as well. Tics of childhood usually disappear as the child gets older. However, the embarrassment of a tic can make a child’s life more difficult in the meantime.

Tics may have a genetic component, as they can run in families.

An increased prevalence of tics is also found in children with attention deficit disorder or obsessive-compulsive behaviors. In fact, some studies report that up to half of children with tics also have attention deficit hyperactivity disorder (ADHD), although there is also some concern that ADHD may be overdiagnosed.

Causes

No one knows exactly what causes tics. Certain neurotransmitters, such as dopamine, are thought to play a role. While tics can run in families, no gene has been clearly identified as being associated with tics.

The most common tic disorder is called “transient tic disorder,” which lasts less than a year. This may be a response to some psychological stress. Tics that last longer than that period of time may signify something more severe, such as haloperidol and risperidone. These drugs can have side effects that include movement disorders and cognitive problems. Clonidine can also be tried, as can tetrabenazine, but these are also not without risks. In extreme cases, deep brain stimulation is being explored as a way of treating intractable Tourette’s syndrome.

In general, because tics usually improve on their own and are not dangerous, most physicians prefer to minimize medical therapy. Counseling of the patient as well as friends, family members and classmates may be one of the best steps to take to help someone with tics.

Sources:

Jankovic J. Movement disorders. In: Goetz, CG, ed. Textbook of Clinical Neurology. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 34.

Kuhn JTO. Deep brain stimulation for psychiatric disorders. Dtsch Arztebl Int. 2010. 107(7): 105-113.

Ostrem, Jill L.; Galifianakis, Nicholas B. Overview of Common Movement Disorders, Continuum : Movement Disorders Volume 16, Number 1, February 2010

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