Tourette syndrome: recent advances. Clinical and genetic studies have allowed the limits of Tourette syndrome to be broadened. There is now strong evidence that chronic motor tics and Tourette syndrome are different manifestations of an autosomal dominant gene with high penetrance. A genetic link with obsessive-compulsive disorder also appears to have been established. Up to 10% of cases of Tourette syndrome may be nongenetic phenocopies, however. There is also an association between Tourette syndrome and attention deficit hyperactivity disorder. This complicates therapy, as psychostimulant drugs may precipitate or exacerbate tics in some individuals. A high proportion of patients with Tourette syndrome also has neuropsychological deficits and learning disabilities. The pathophysiology is incompletely understood. The best supported hypothesis is that there is dopamine receptor supersensitivity, although there are strong suggestions of abnormalities in serotonin metabolism. The possibility of abnormalities in neuropeptide systems is being explored. Treatment of tics relies primarily on neuroleptics with dopamine receptor blocking activity. Clonidine may be useful in some patients, especially those with behavior problems. Obsessive-compulsive symptoms can be treated using appropriate pharmacologic agents. The treatment of attention deficit disorder in patients with tics should begin with behavioral strategies. Clonidine can be tried as the first-line drug, and psychostimulants should be used only if necessary and with great caution. In rare instances it may be necessary to combine a psychostimulant and a neuroleptic. 