Tourette's disorder

Content provided by the Faculty of the Harvard Medical School

Tourette's disorder

“My neck cranes to the right, then the muscles of the left side of my face and neck contract, squinting my left eye and tilting my head briefly forward. My left arm arises until my hand halts directly in front of my face. I am frozen for a moment; I emit a tiny — almost inaudible — whoop. And then I go back to my writing for half a minute or so until a whole collection repeats itself. … I am in a university library, surrounded by strangers, and so I painstakingly sublimate these tics, disguising them as stretches, glances around the room, and throat clearing.” – P.J. Hollenbeck, 2003

The symptoms were first described more than a hundred years ago by the French neurologist Gilles de la Tourette, and his name has been given to the disorder now regarded as the most common cause of tics — brief intermittent involuntary or semi-voluntary movements or sounds. According to the American Psychiatric Association, a diagnosis of Tourette’s disorder requires many motor tics (movements) and at least one vocal or phonic tic (sound), with symptoms beginning before age 18 and lasting more than a year.

Often the earliest signs are rapid blinking and twitching of the mouth and nose. Other motor tics are head jerking, tooth grinding, neck twisting, abnormal postures and muscle contractions. More complex movement tics include facial contortions, squatting, deep knee bends, bowing, jumping, obscene gestures and imitation of other people’s gestures.

Vocal or phonic tics include sniffing, throat clearing, squeaking, barking, grunting, humming, blowing or sucking sounds, repeating one’s own or someone else’s words, and spewing obscenities.

Obscene gestures and speech are the most conspicuous and disturbing symptoms of Tourette’s but not the most common, frequent, or persistent — probably no more than 10% of people with the disorder ever have these symptoms.

Tics are not entirely automatic. The need to perform a tic may resemble the need to sneeze or scratch an itch. There may also be a feeling of tension or tightness or a less specific urge or anxiety. Many people with Tourette’s say they have to repeat their tics until it “feels right.” Often they try to disguise tics as normal movements and sounds (as in the quotation above), or control themselves in company and then “release” the tics when they are alone. The symptoms become worse under stress, although they may also occur during sleep. Tics tend to go away during intense concentration.

Tourette’s is mainly a disorder of childhood and adolescence, with the first symptoms appearing at an average age of six. About 10% of children have some tics and 1% have Tourette’s disorder. Most tics fade by age 18, and even when they persist in adulthood, they are likely to become less severe.

The disorder is three times more common in boys than in girls, and it has a strong genetic component. The chance that a parent, brother, sister, or child of a person with the disorder will have at least some chronic tics is about 25%. The concordance (matching) rate for Tourette’s disorder itself is 90% in identical twins.

Many children and adults with Tourette’s, especially those whose symptoms are mild, do not have any other psychopathology. But children with a tic disorder serious enough to bring them to a clinic often have other problems, especially attention deficit hyperactivity disorder and obsessive-compulsive disorder. About 50% of people with Tourette’s suffer from obsessive thoughts and compulsive rituals as well as tics, and the rate of obsessive-compulsive disorder in their families is 10%–15%, compared to 2%–3% in the general population.

In fact, complex tics are not always easy to distinguish from compulsive rituals. They look like deliberate actions rather than reflexes, they are preceded by urges and anxiety, and they can be suppressed by an act of will or disguised by transformation into apparently purposeful movements. Tourette’s syndrome is sometimes regarded as part of the obsessive-compulsive spectrum — a range of compulsions with simple tics at one extreme and complex rituals and obsessional thoughts at the other.

Shared genetic vulnerability and sometimes similar symptoms suggest that the same brain regions are affected in Tourette’s disorder and obsessive-compulsive disorder. The circuit probably involved runs between the prefrontal cortex, a center of judgment and decision making, and the basal ganglia, which help control body movements. In people with Tourette’s, the size of the caudate nucleus, part of the basal ganglia, may be smaller than average. Stimulation of the basal ganglia in animals can provoke responses that resemble tics. Certain regions of the prefrontal cortex and basal ganglia become more active both when a person with Tourette’s syndrome is suppressing tics and when a person with obsessive-compulsive disorder has obsessional thoughts. It’s possible that in both of these disorders the basal ganglia are not supplying the feedback that the frontal lobes need to make decisions about moving the body. In Tourette’s syndrome, excessive activity of the neurotransmitter dopamine may be involved.

Many people with Tourette’s are never diagnosed, because they are embarrassed by their tics and able to suppress them during visits to a doctor. Treatment is necessary mainly when the tics are disruptive, frightening, or bizarre, and provoke ridicule and rejection. More often, associated problems of attention deficit disorder and obsessive-compulsive behavior bring a person with Tourette’s to medical attention.

A common treatment is a low dose of an antipsychotic medication that blocks receptors for dopamine. Today the older drug haloperidol (Haldol) is giving way to the second-generation antipsychotics risperidone (Risperdal) and olanzapine (Zyprexa), which have fewer troublesome side effects. Still, these drugs may cause drowsiness, increased appetite, weight gain, and possibly a rise in blood sugar. Other second-generation antipsychotic drugs, aripiprazole (Abilify) and ziprasidone (Geodon) are less likely to cause weight gain.

The blood pressure-lowering medication clonidine, which affects dopamine receptors indirectly, has also been found effective in suppressing tics. Its main side effect is drowsiness. The antianxiety drug and muscle relaxant clonazepam (Klonopin) may be useful, and one controlled study has found that the symptoms are improved by delta-9-tetrahydrocannabinol, the active ingredient in marijuana. It may take months to determine the effectiveness of any drug, because the symptoms of Tourette’s come and go spontaneously and unpredictably.

Matters can become more complicated when Tourette’s is accompanied by other disorders. Some believe that tics can be exacerbated by stimulants, which are used to treat attention deficit disorder, and selective serotonin reuptake inhibitors, which are used to treat obsessive-compulsive disorder. There are no controlled studies including only patients with both obsessive-compulsive disorder and Tourette’s syndrome.

A simple motor tic can be suppressed for a few months at a time with an injection of botulinum toxin (Botox) that paralyzes the muscle involved. This approach is obviously impractical for more complex tics or for a person with many shifting tics.

Behavioral techniques may help, as in the treatment of obsessive-compulsive disorder. One controlled study found that a method called habit reversal is effective. Patients learn to describe their tics in detail, identify the situations in which they occur, and stop themselves by, for example, contracting muscles that oppose the tic. They also receive relaxation training and reward themselves for success (operant conditioning).

Psychotherapy may be useful if the tics cause loss of self-esteem, anxiety, depression, or social difficulties. Some children need a break during school to release the tics. A few may require tutoring or special schools because of tics that disrupt classrooms. Some adults need special accommodations in the workplace. But it’s important to remember that in many cases the symptoms are mild and require nothing more than explanation and reassurance.

More accurate brain imaging and genetic studies may lead to the development of drugs and other treatments specifically designed for Tourette’s syndrome and even for individual patients. Meanwhile, Tourette’s is especially interesting to some scientists because its symptoms lie on the border between the voluntary and the involuntary, the physical and the mental, the normal and the pathological. A better understanding of these symptoms could lead to a better understanding of many other neurological and behavior disorders.

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Last updated:	August 21, 2006