The observed pattern of genetic correlations with psychiatric, personality, educational, and metabolic phenotypes provides grounds for broadening our conceptualization of the disorder. First, the strong positive genetic correlations of anorexia nervosa with obsessive-compulsive disorder and neuroticism reinforce clinical and epidemiological observations. AN is commonly comorbid with OCD and twin studies have reported high twin-based genetic correlations (27). High neuroticism in adolescence predicts subsequent onset of AN (1). In addition, anorexia nervosa is commonly comorbid with multiple anxiety phenotypes, which often pre-date the onset of anorexia nervosa (28).
