Tourette syndrome is a complex neurological disorder that is characterized by repetitive, sudden, uncontrolled (involuntary) movements and sounds (vocalizations) called tics. Tourette syndrome is named for Georges Gilles de la Tourette, a French physician and neurologist, who first described this disorder in 1885. A variety of genetic and environmental factors likely play a role in causing Tourette syndrome. A small number of people with Tourette syndrome have been found to have mutations involving the SLITRK1 gene. The syndrome is believed to 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.
It is estimated that about 1% of the population has Tourette syndrome. 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. 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.