Shared transmission of eating disorders and anxiety disorders

Objective: Eating disorders have high comorbidity with mood, anxiety, and substance use disorders. Using twins from the population-based Minnesota Twin Family Study (MTFS), we examined comorbidity and shared transmission between eating pathology and these disorders. Method: Female twins (N = 672), ages 16-18 years, completed structured clinical interviews assessing anorexia nervosa and bulimia nervosa (as described in the 4th ed. of the Diagnostic and Statistical Manual of Mental Disorders [DSM-IV; American Psychiatric Association, 1994]), as well as mood, anxiety, and substance use disorders (as described in the 3rd Rev. ed. of the Diagnostic and Statistical Manual of Mental Disorders [DSM-III-R]). Shared transmission was examined using a discordant monozygotic (MZ) twin design. Results: Significant comorbidity was found between eating disorders and major depression, anxiety disorders, and nicotine dependence. Within MZ twin pairs discordant for eating disorders (n = 14), non-eating-disordered cotwins demonstrated increased risk for anxiety disorders compared with controls. Similarly, within MZ twin pairs discordant for anxiety disorders (n = 52), non-anxiety-disordered cotwins demonstrated increased risk for eating disorders compared with controls. Discussion: Findings support shared transmission between eating disorders and anxiety disorders. However, the nature of this shared diathesis remains unknown.