title: Generalized anxiety disorder and anorexia nervosa: evidence of shared genetic variation.
abstract: BACKGROUND
  Previous studies have indicated a high prevalence of generalized anxiety disorder (GAD) in women with anorexia nervosa (AN). However, the shared genetic and environmental components of these disorders have not been explored. This study seeks to elucidate the shared genetic and environmental components between GAD and AN.
  
  
  METHODS
  Using 2,083 women from the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders, structural equation modeling was used to obtain maximum likelihood estimates of the environmental genetic, shared and unique environmental components in 496 women with GAD, 47 women with AN, 43 women with GAD + AN, and 1,497 women without GAD or AN.
  
  
  RESULTS
  Results show that the heritability of GAD was 0.32 and AN was 0.31, and the genetic correlation between the two disorders was 0.20, indicating a modest genetic contribution to their comorbidity. Unique environment estimate was 0.68 for GAD and 0.69 for AN, with a unique environmental correlation of 0.18. All common environmental parameters were estimated at zero.
  
  
  CONCLUSIONS
  The modest shared genetic and unique environmental liability to both disorders may help explain the high prevalence of GAD in women with AN. This knowledge could help in the treatment and prevention of comorbid disorders.
authors: Virginia Institute for Psychiatric and Behavioral Genetics, Virginia Commonwealth University, Richmond, Virginia 23298, USA. jdellava@vcu.edu
authors: Jocilyn E
authors: JE
authors: Dellava
authors: Kenneth S
authors: KS
authors: Kendler
authors: Michael C
authors: MC
authors: Neale
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