Tourette syndrome is a disorder of the nervous system that causes a person to make repeated and uncontrolled (involuntary) movements and sounds (vocalizations) called tics. Tourette syndrome is named for Georges Gilles de la Tourette, who first described this disorder in 1885. There is strong evidence that Tourette syndrome is passed down through families, although the gene has not yet been found. The syndrome may be linked to problems in certain areas of the brain, and the chemical substances (dopamine, serotonin, and norepinephrine) that help nerve cells talk to one another. Tourette syndrome can be either severe or mild. It is estimated that about 1% of the population has Tourette syndrome.^[3] Many people with very mild tics may not be aware of them and never seek medical help.   Tourette syndrome is four times as likely to occur in boys as in girls.^[1]  Although Tourette syndrome can be a chronic condition with symptoms lasting a lifetime, most people with the condition experience their worst symptoms in their early teens, with improvement occurring in the late teens and continuing into adulthood.^[2]