ABSTRACT
Epidemiologists investigate the effects of a disorder within groups of people rather than in individuals. Through the application of epidemiological principles, we can learn about the magnitude and distribution of a disorder, evaluate the social and economic consequences of being affected, and develop and test theories about the cause of the disease. This chapter briefly introduces some epidemiological terms and provides a short review of epidemiological studies of tic disorders, particularly Gilles de la Tourette’s syndrome (TS). Topics such as the genetic epidemiology of TS that might normally be considered in a chapter on epidemiology are covered in other chapters in this volume.
