Tourette Syndrome Health Article

Tourette Syndrome

A genetic, neurological disorder characterized by motor and vocal tics and associated behavioral features including obsessions and compulsions and hyperactivity.

Tourette syndrome (TS) affects roughly one in every 2,500 persons. The incidence of the condition is at least three times higher in males than in females. Historically, Tourette syndrome has been a largely misunderstood condition; it has been identified as demonic possession, epilepsy, schizophrenia, and other mental disorders and was formerly thought to be the result of emotional problems due to faulty childrearing. The condition was first identified as a physiological disorder in 1885 by the French neurologist Gilles de la Tourette. Although the causes of Tourette syndrome are still not fully understood, researchers have made substantial progress in understanding and treating the condition.

Symptoms

Tics—sudden, repetitive, involuntary muscular movements—are the hallmark of Tourette syndrome, appearing in two forms: motor and vocal tics. Motor tics are uncontrollable body movements, such as blinking, grimacing, shrugging, or tossing one's head. Vocal tics, which involve the muscles that produce speech, take the form of uncontrolled speech and involuntary noises, including snorting, hissing, yelping, sniffing, grunting, throat-clearing, and yelling. For a diagnosis of Tourette syndrome to be made, the Diagnostic and Statistical Manual (DSM-IV) of the American Psychiatric Association specifies criteria, including multiple motor tics and at least one vocal tic, occurring numerous times every day or almost daily for a period of over one year, with no tic-free period longer than three months, and onset of symptoms before the age of 18. There are two basic types of tics: simple and complex. Simple tics are isolated movements (such as blinking, kicking, or twitching) that involve only one part of the body. Complex tics are more involved and take the form of recognizable actions, such as poking, hitting, biting, and grooming behaviors (such as smoothing one's hair). They also include imitating the actions of others and making involuntary obscene gestures. Complex vocal tics involve recognizable words (or animal sounds) as opposed to simple noises. These may include the repetition of short phrases, such as "Oh, boy," the repetition of a single word, repetition of the words of others (echolalia), or involuntary swearing (coprolalia), which is one of the most publicized symptoms of the disorder, although it affects fewer than 10% of people with TS.

Besides tics, there are several types of behavior often associated with Tourette syndrome. At least half the persons affected with TS show symptoms of obsessive-compulsive disorder (OCD), a psychological condition that involves repeated intrusive and senseless thoughts (obsessions) and repetitive behavior (compulsions) intended to stop them. An obsession may be an ordinary but inappropriately intense desire (such as a preoccupation with visiting a certain store) or an outlandish idea, such as a wish to walk across the dinner table or touch a stranger. Compulsions are pointless activities that a person with OCD can't help repeating, such as turning lights on and off, counting things over and over, or arranging objects in a certain pattern. OCD symptoms can be extremely debilitating, taking time away from normal pursuits, including schoolwork and social activities. The other major behavior disorder associated with Tourette syndrome is attention deficit/hyperactivity disorder (ADHD), whose symptoms include hyperactivity, inability to concentrate, and impulse control disorders. Some persons with Tourette syndrome have both OCD and ADHD.

Causes and onset of Tourette syndrome

Tourette syndrome, once thought to be caused by psychological problems, is now known to be a genetic disorder. About 90% of children with TS have a family history of TS or related disorders, such as other conditions involving tics. Some persons are genetic carriers of Tourette syndrome without actually having symptoms themselves (these are almost always females; roughly 99% of males who carry the genetic tendency toward the disorder develop symptoms). The biological basis for Tourette syndrome is an imbalance in the brain's neurotransmitters, chemicals that transport messages between nerve cells. The main neurotransmitter affected in people with TS is dopamine, which controls movement. Research has shown that two other neurotransmitters, norepinephrine and serotonin, also play a role in the condition. In addition, imaging techniques, such as brain scans, have shown abnormalities in the size and functioning of certain parts of the brain in persons affected by TS.

Symptoms of Tourette syndrome usually appear before the age of 18. Children with TS develop their first tics at the age of six or seven but show other signs of the disorder, including sleep problems, language difficulties, and oppositional behavior, in early childhood, often by the age of two or three. TS usually starts with a single tic, often in the head area (most frequently repeated blinking). The initial tics are generally simple motor tics in the head and upper extremities. As the disorder progresses, the tics gradually move downward to include the torso and lower extremities. Vocal tics usually begin at about the age of nine; complex vocal tics such as coprolalia are among the last to appear. Tics in people with TS are suppressed under certain conditions, usually during sleep and when an individual is engaged in an activity that requires intense concentration. In some cases, children with TS can even manage to keep their tics under control voluntarily in situations where they fear embarrassment, although this takes an immense effort and afterwards the suppressed tics emerge with even greater force than usual. The symptoms of Tourette syndrome increase through childhood and peak during adolescence, after which their intensity usually decreases. An estimated 20-30% of all children with TS outgrow the condition entirely by adulthood.