Tics are abrupt, purposeless, and involuntary vocal sounds or muscular jerks. They are sudden, rapid, and recurrent. They can involve any body part and may vary in severity - from very mild and hardly noticeable to very disruptive, frequent, and severe.
Nearly 5 to 24 percent of school-aged children experience transient tic disorder—the most common type of tic disorder, with symptoms lasting at least four months, but no longer than one year. Symptoms of transient tic disorder may be more prevalent in periods of stress, fatigue, or as a result of certain types of medications, and may be confused with other symptoms of nervousness, anxiety, or restlessness that many children experience.
Tics which are seen lasting more than one year are classified as chronic tics. Chronic tics affect less than 1 percent of school-aged children and must be differentiated from Tourette's disorder, in which multiple motor tics and at least one or more vocal tics must be present.
Tic disorders are generally differentiated based on the type of tics present, the age of onset of symptoms, and the duration of symptoms.
Tourette's disorder (TD), sometimes called Tourette's syndrome (TS), is a neurological disorder characterized by multiple repeated tics. Tics are abrupt, purposeless, and involuntary vocal sounds or muscular jerks. Symptoms of TD usually begin between the ages of five and 10 years of age, and usually begin with mild, simple tics involving the face, head, or arms. With time, tics become more frequent and increase in variety, involving more body parts such as the trunk or legs, and often become more disruptive to activities of daily living (ADLs).
Tourette's disorder is an autosomal dominant disorder. Autosomal means that both males and females are affected, and dominant means that one copy of the gene is necessary to have the condition. This means that a parent with TD or a parent who has the gene for TD has a 50/50 chance, with each pregnancy, to pass the gene on. TD is associated with a non-genetic cause in 10 percent to 15 percent of children. Complications of pregnancy, low birth weight, head trauma, carbon monoxide poisoning, and encephalitis are thought to be associated with the onset of non-genetic TD.
Dominant disorders exhibit something known as incomplete penetrance, which means that not everyone with the gene will have symptoms of Tourette's disorder. In other words, if a parent passes the gene on to a child, the child may not have any symptoms of the disorder. If a daughter inherits the gene, there is a 70 percent chance that she will have at least one of the signs of TD. On the other hand, if a son inherits the gene, there is a 99 percent chance that he will have at least one of the signs of TD.
Finally, dominant disorders can also exhibit something known as variable expressivity. This means that there are differences in the expression of the TD gene in different people. For example, one person with TD may have obsessive-compulsive disorder, while another has a chronic tic disorder, while another has full-blown TD. In addition, there are differences in expressivity between males and females: males are more likely to have full-blown TD or chronic tics, while females are more likely to have obsessive-compulsive disorder.
A diagnosis of TD is generally made before the child reaches his or her 18th birthday. In the majority of cases, a child is diagnosed around the age of 7. TD affects more males than females.
Tic behaviors seen in TD change over time, and vary in frequency and complexity. The following are the most common tic behaviors associates with TD. However, each child experiences symptoms differently. Symptoms may include:
Some of the more complex tic behaviors associated with TD may appear purposeful, and may include the following:
In addition to some, or all, of the above symptoms, TD is also characterized by one or more vocal tics (meaningless sound), in order for a diagnosis of TD to be made, including the following:
Many children and adolescents who have TD also have attention problems and some also have academic difficulties. However, most have normal intelligence and do not usually have primary learning disabilities. Some individuals also experience symptoms of obsessive-compulsive disorder (OCD), which is an anxiety disorder in which a person has an unreasonable thought, fear, or worry (obsession) that he or she tries to manage through a ritualized activity (compulsion) to reduce the anxiety.
The symptoms of TD may resemble other conditions or medical problems. Always consult your child's health care provider for a diagnosis.
A pediatrician, child psychiatrist, or a qualified mental health professional usually identifies TD in children and adolescents. A comprehensive evaluation of the child or adolescent's psychological, social, and educational status is recommended, as well as a thorough medical, developmental, and family assessment. A detailed history of the child's behavior from parents and teachers, in addition to observations of the child's behavior, contribute to making the diagnosis.
Specific treatment for Tourette's disorder will be determined by your child's health care provider based on:
The effect of symptoms on the child's or adolescent's self-concept, family and peer relationships, and classroom participation determines what needs are to be addressed in treatment. In many cases, TD is not disabling. Development may proceed normally, and there is no need for treatment. However, when tics interfere with functioning or school performance, and/or if there are other disorders also present (i.e., obsessive-compulsive disorder, attention deficit/hyperactivity disorder), some effective medications are available. Children with TD can generally function well at home and in a regular classroom. If they have accompanying emotional or learning problems, they may require special classes, psychotherapy, and/or medication.
The genetics behind Tourette's disorder are complicated. For this reason, it is important for individuals and families with Tourette's disorder to have genetic counseling by a geneticist (a physician with specialized training and certification in clinical genetics) or a genetic counselor, once a diagnosis has been made in the family.
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