Environmental Risk Factors in Tic Disorders

ABSTRACT

Tic disorders, including Tourette syndrome, are known as neurobiologic disorders and as such, much emphasis has been placed on isolating genetic determinants. Although previous reports involving studies of discordance among monozygotic twins have shown the importance of genetic predisposition, they have also supported a role for environmental factors in the development of tic disorders. Therefore, it is important to consider that both genetic and environmental factors contribute to their clinical expression. The goal of this article was to review recent reports regarding the role of environmental factors in development and progression of tics. Specific environmental factors associated either with a more severe course of illness or improved outcomes were discussed. Given that accumulating evidence had suggested the usefulness of behavior therapies in the suppression of tic disorders, particular emphasis was placed on the impact of several contextual factors.