Why do some individuals develop social phobia? A review with emphasis on the neurobiological influences.

Social phobia, or social anxiety disorder, is now considered the most common anxiety disorder. Still, the etiology of the disorder is to an essential degree unknown. This paper presents an overview of various pathways to be considered in relation to the development of social phobia. The literature concerning genetics and family aggregation, behavioral inhibition, various forms of the learning account, and neurobiological influences was examined. The reviewed studies suggest that social phobia has a neuroanatomical basis in a highly sensitive fear network centered in the amygdaloid-hippocampal region, i.e. "the alarm system" of the brain, and encompassing the prefrontal cortex. This pattern is congruent with genetic studies proposing that the genetic component comprises a general vulnerability to fearfulness rather than to social phobia itself. Further, both family and twin studies support a hereditary contribution to social phobia resulting from genetic and environmental factors, which most likely operate in an interactive way rather than acting in isolation.