ABSTRACT
I.GENETIC EPIDEMIOLOGY OF SOCIAL ANXIETY AND RELATED TRAITS
A.Introduction
Among the anxiety disorders, social anxiety disorder has garnered increased attention in recent years, owing in part to the demonstration of its high prevalence and marked impact on functioning (1, 2). Social anxiety disorder is associated with numerous adverse psychosocial and socioeconomic outcomes, including early dropout from school, reduced job earnings, increased direct and indirect health care costs, and poor health-related quality of life (3-5) (this volume, Baldwin and Buis). The study of social anxiety disorder from a genetic perspective is particularly compelling for several reasons. First, social anxiety disorder is heritable (6, 7), particularly in its more severe form, generalized social phobia (GSP) (8). Second, GSP is an early-onset disorder, with over 90% of cases occurring by the early teen years (9); this makes it possible to study young adults with a very low risk of phenotypic misclassification. Third, the relationship between certain heritable quantitative traits (e.g., social interactional anxiety) and GSP has been sufficiently well studied that this provides an additional opportunity to find linkage to a phenotype that may be closer to biological reality than that provided by the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (10, 11). For all these reasons, further exploration of the genetic bases for social anxiety disorder and related traits will be a worthwhile endeavor. In this chapter, we review the available evidence for the heritability of social anxiety disorder and characterological traits that
may underlie this disorder. We also consider possible candidate genes for social phobia. Finally, we review the very small but growing literature implicating particular genes or genomic regions as susceptibility factors for social anxiety disorder and related traits.
