The genetic basis of panic and phobic anxiety disorders.

Panic disorder and phobic anxiety disorders are common disorders that are often chronic and disabling. Genetic epidemiologic studies have documented that these disorders are familial and moderately heritable. Linkage studies have implicated several chromosomal regions that may harbor susceptibility genes; however, candidate gene association studies have not established a role for any specific loci to date. Increasing evidence from family and genetic studies suggests that genes underlying these disorders overlap and transcend diagnostic boundaries. Heritable forms of anxious temperament, anxiety-related personality traits and neuroimaging assays of fear circuitry may represent intermediate phenotypes that predispose to panic and phobic disorders. The identification of specific susceptibility variants will likely require much larger sample sizes and the integration of insights from genetic analyses of animal models and intermediate phenotypes.