What is the relationship between depression and eating disorder?

Dep and eating d/o: Although a loss of appetite can be a symptom of major depression, it does not cause anorexia nervosa or bulemia. Conversely, it is not uncommon to see depression in those dealing with an eating disorder. Antidepressants have been used in treating eating disorders to stimulate appetite or offset depressive symptoms. They do little, however, to actually treat the eating disorder.

Comorbidities: Eating disorder is a subset of anxiety disorder/ocd. These conditions are highly comorbid with depression. All comorbidites need to be treated simultaneously to improve the target condition. The nimh reported "extremely" high incidence of depression in women with eating disorders. http://www.ncbi.nlm.nih.gov/pubmed/16738079. It's important to recognize & treat depression in this group of patients.