An update on Tourette syndrome.

This summary of the present status of tic disorders in based on our experience with 650 patients and review of the literature. The three major tic disorders, Transient Tic of Childhood, Chronic Motor Tic, and Tourette syndrome, now thought to have similar organic etiology, form a continuum with heterogeneity of symptoms and severity. This paper summarizes current understanding of the demography, illness-related characteristics, psychopathology, neuropathology, genetics, neurochemistry, and treatment.