The Prevalence, Incidence, and Risk of Tourette Syndrome

Abstract

Abstract This chapter summarizes the results and discusses the methodological issues related to prevalence studies on Tourette syndrome (TS) conducted during the past two decades. The best estimate for the prevalence of TS in school-age children is between 5 and 7 cases per 1,000. The prevalence of chronic motor tic disorder appears to range from 3 to 8 per 1,000, whereas estimates of prevalence for chronic vocal tic disorder in school-age children are less stable and await further study. Children with chronic tic disorders, even those with mild conditions, have a higher likelihood of other problems, such as attention-deficit/hyperactivity disorder, disruptive behavior, and obsessive–compulsive disorder. The classic two-stage design seems to be an acceptable approach for prevalence studies of TS and related tic disorders; however, this requires sample sizes greater than 5,000 to ensure relatively narrow confidence intervals. From a public health perspective, chronic tics may serve as a marker of neurodevelopmental vulnerability. Community-based studies that improve case finding and register-based studies may also improve our comprehension of the public health impact of tic disorders in children.