Anorexia nervosa and generalized anxiety disorder: Further explorations of the relation between anxiety and body mass index

We explore comorbidity of anorexia nervosa (AN) and generalized anxiety disorder (GAD) and their relation with body mass index (BMI) and evaluate the presence of fasting and excessive exercise which both have anxiolytic and weight loss effects. All participants were female: 32 with AN only, 607 with GAD only, 22 with AN and GAD (AN + GAD), and 5424 with no history of AN or GAD (referent) from the Swedish Twin study of Adults: Genes and Environment (STAGE). Lowest adult BMI differed significantly (p < .001) and was lower in those with AN + GAD than those with AN only (p < .029). Those with AN + GAD were most likely to endorse fasting and excessive exercise, followed by women with AN only, women with GAD only, and the referent. Comorbid AN and GAD may be a particularly pernicious presentation influencing both BMI and proclivity to engage in behaviors such as fasting and exercise that serve both weight loss and anxiolytic goals.

► Anorexia nervosa and generalized anxiety disorder are commonly comorbid.
► Individuals with comorbid anorexia nervosa and generalized anxiety disorder may be at increased risk for lower illness-related body mass indices.
► Individuals with comorbid anorexia nervosa and generalized anxiety disorder as well as individuals with generalized anxiety disorder only are more likely to engage in fasting and excessive exercise.
► Comprehensive screening for anxiety disorders in individuals presenting with anorexia nervosa is vital.
► Screening for behaviors such as fasting and excessive exercise in individuals with generalized anxiety disorder may also be warranted.