The Prevalence of Tourette Syndrome and its Relationship to Clinical Features

Abstract

Abstract This chapter will summarize the results of and discuss the methodological issues related to the prevalence studies on Tourette syndrome conducted over the past 12 years. The best estimate for the prevalence of Tourette syndrome in school-age children is likely to fall between 5 and 7 cases per 1,000. The prevalence of chronic motor tic disorder in school-age children ranges from 3 to 8 per 1,000, whereas estimates of prevalence for chronic vocal tic disorder 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 an acceptable approach for prevalence studies of Tourette syndrome 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 are likely to increase our understanding of the health impact of tic disorders in children.