Genetics of anxiety and trauma-related disorders

Anxiety disorders are the most common psychiatric illnesses in the United States with approximately 30% of the population experiencing anxiety-related symptoms in their lifetime [Kessler RC, Berglund P, Demler O, Jin R, Merikangas KR, Walters EE (2005) Lifetime prevalence and age-of-onset distributions of Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV) disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry 62:593-60]. Notably, a variety of studies have demonstrated that 30-40% of the variance contributing to these disorders is heritable. In the present review, we discuss the latest findings regarding the genetic and environmental influences on the development and symptomatology of anxiety disorders. Specific emphasis is placed on posttraumatic stress disorder (PTSD) due to its uniqueness as an anxiety disorder; its diagnosis is dependent on a precipitating traumatic event and its development appears to be mediated by both genetic and environmental contributions. The co-morbidity of anxiety disorders and the potential re-classification of anxiety disorders as part of DSM-V are reviewed given the potential impact on the interpretation and design of genetic investigations. Lastly, several keys to future genetic studies are highlighted. Thorough analyses of the gene by environment (GxE) interactions that govern one's vulnerability to anxiety disorder(s), the effectiveness of individual treatment strategies, and the severity of symptoms may lead to more effective prophylactic (e.g. social support) and treatment strategies.