Tic disorders are neurological * conditions characterized by sudden rapid movements (for example, neck jerking) or sounds (words or other types of sounds, such as grunting or sniffing) that are repeated in a consistent pattern many times per day.
Tics have been described as brain-activated involuntary movements or sounds, meaning that the person with a tic does not produce the behaviors intentionally. People with tics can often suppress them, sometimes for up to hours at a time. A parallel example would be trying to suppress a cough in the middle of a concert. To avoid interrupting the musicians, people might try hard not to cough until the intermission. When they finally do cough, they might cough several times instead of just once or twice. The experience of trying to suppress a tic is similar. After a tic is suppressed, it may erupt with even greater force or frequency.
Tics tend to get worse when people feel anxious or tired, and are less bothersome when they are calm and focused on an activity. One interesting aspect of the condition is that tics usually lessen around strangers and are expressed more freely among family members and other trusted people. This difference probably reflects the fact that individuals work harder to suppress tics in less comfortable situations, whereas they naturally let down their guard when they are in more familiar surroundings. It is not uncommon for a child to be taken to a doctor to diagnose the problem, only to have the child be unable to produce tics “on command.” Just as tics are experienced as uncontrollable, they cannot be voluntarily brought on. While tics may appear in individuals as early as two years of age, the average age at onset is about seven.
Simple tics involve a single movement, such as eye blinking or repeatedly sticking out the tongue. Tics may also be vocal, made up of a single sound like throat clearing or snorting, stuttering, or sniffing. The most common type of tics, and often the first to appear, are simple facial tics. Over time, more complex motor * tics may appear.
Complex motor tics involve several coordinated muscle movements, such as touching or smelling an object, jumping or twirling, or making deep knee bends while walking. These tics may include neck stretching, foot stamping, body twisting and bending, or mimicking the gestures of other people. Complex vocal tics can range from combining simple throat clearing or grunting with other vocal behaviors to repeating a long but meaningless string of words at regular intervals.
With complex tics, the repeated phrase or gesture at first may seem meaningful even when it is not. For example, the person with a complex motor tic may feel a need to do and then redo or undo the same action several times (for example, stretching out one arm 10 times before writing or retracing the same letter or repeating the same word) before proceeding to another activity. Such forms of behavior can interfere with a person's ability to accomplish school- or work-related tasks.
Researchers have identified more than 80 tics, which are a mix of simple and complex motor and vocal tics. Recognizable tic patterns include:
The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) reclassified tic disorders into three categories: Tourette syndrome; persistent (chronic) motor or vocal tic disorder; and provisional tic disorder.
TS is the best-known of the tic disorders. Persons diagnosed with it have both motor and vocal tics, and have had the tics for at least one full year. TS is named for Gilles de la Tourette (1857–1904), a French neurologist who published a case series of nine patients with TS in 1885.
People with persistent motor or vocal tic disorders have either motor or vocal tics, but not both, and have had tic symptoms for at least one year.
To be diagnosed with provisional tic disorder, a person must:
While there are clear differences between tic disorders, a doctor may find it difficult to make a diagnosis because tics often change in type or frequency over time. Provisional tics, for example, are short-lived tics that have been present for less than a year, but a child may experience a series of provisional tics over a period of several years. Neck jerking may last for several months and then be replaced by finger snapping or stamping in place. Persistent tics, by contrast, last longer than a year and tend to remain stable and constant over time.
Provisional tics that change over time are believed to affect as many as one-fourth of all school-aged children, with boys three times more likely than girls to develop a tic disorder. While they last, these tics may be quite unusual. They might range from sticking out the tongue again and again to repeating a word or phrase a set number of times to poking or pinching various parts of the body. These strange kinds of behavior are more common than was once believed, but often they disappear as a child matures. By age 18, about 50 percent of children with tic disorders are free of tics.
Distinguishing provisional tics from persistent tics often requires careful evaluation by a physician over a period of years. In addition, it is important for a doctor to gather information about other members of the family (including parents, grandparents, and siblings) who also may have tics or related conditions. It is now known that the tendency for tics to develop is passed on genetically * (inherited) from generation to generation. Because a person may inherit a genetic tendency to tic disorders without ever experiencing tics, it is possible for the disorder to skip several generations in one family. Researchers have attempted to identify the specific gene (or genes) for tic disorders and to understand other factors that may influence whether a person at risk actually will experience tics.
In 2011, the DLGAP3 on the short arm of chromosome 1 was identified as a possible candidate gene for TS. However, as of 2016 most researchers think that several genes not yet identified play a role in tic disorders, and that there are also nongenetic causes of these disorders. Some doctors think that these causes may include environmental toxins, autoimmune disorders, or streptococcal infections.
For most people who have tics, the real threat may not be the tics themselves but the sense of shame and social isolation that can result from these odd or eccentric gestures or sounds. A child may have great difficulty dealing with these embarrassing, unwanted behaviors. It may also be hard for teachers, fellow students, and family members to understand that a person with a tic disorder is not making these strange gestures and sounds intentionally to gain attention or to avoid working. Other people can easily get that impression if the pattern of tics changes from day to day, as it often does. It can make matters even more difficult when tic disorders in children are associated with attention disorders, hyperactivity, impulsive behavior, obsessive-compulsive disorder * , irritability, or aggressiveness.
It is estimated that as many as half of the children with Tourette syndrome also have the attention and impulse-control problems that are seen in attention deficit hyperactivity disorder. Children with Tourette syndrome also have higher than average rates of learning disabilities that cause reading or language problems.
There are several therapies to help children with tics cope with the frightening feelings of being out of control and with the specific types of behavior related to their condition. These include relaxation and stress-reduction techniques and biofeedback. Often medication is an important part of the treatment plan, along with a form of behavioral therapy known as habit reversal therapy, or HRT. In habit reversal therapy the child or teenager is taught to replace a tic with a less obvious or objectionable movement or sound whenever he or she is aware of the urge to express the tic. HRT is reported, as of 2016, to be as effective as medications in reducing the severity of tics.
Because of associated stress, anxiety, and self-esteem and relationship issues, working with a mental health professional when concerns begin to interfere with the quality of the child's life is particularly important. A combination of treatment approaches is often required when tics and associated mental health problems are serious.
See also Anxiety and Anxiety Disorders: Overview • Attention Deficit Hyperactivity Disorder (ADHD) • Genetic Diseases: Overview • Learning Disabilities: Overview • Obsessive-Compulsive Disorder • Tourette Syndrome
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* neurological (nur-a-LAH-je-kal) refers to the nervous system, which includes the brain, spinal cord, and the nerves that control the senses, movement, and organ functions throughout the body.
* motor relates to body movement.
* genetically (je-NE-ti-klee) means stemming from genes, the material in the body that helps determine a person's characteristics, such as hair or eye color.
* obsessive-compulsive disorder is a condition that causes people to become trapped in a pattern of repeated, unwanted thoughts, called obsessions (ob-SESH-unz), and a pattern of repetitive behaviors, called compulsions (kom-PUL-shunz).