Differential diagnosis and pathogenesis of anorexia nervosa.

Anorexia nervosa is a disease of increasing frequency with serious medical and psychological consequences. The presentation is one of significant weight loss. The initial assessment of such a patient must differentiate between an underlying systemic medical illness and an eating disorder. This paper will review the more common medical conditions causing weight loss and their distinguishing characteristics, including malignancy, inflammatory bowel disease, infections and metabolic disorders. Once an organic disease is ruled out, anorexia nervosa must then be differentiated from other eating disorders such as bulimia or other psychological diseases such as depression, schizophrenia, drug abuse, conduct disorders, and anxiety reactions. The pathogenesis of anorexia nervosa includes complex societal, family, and individual factors which require evaluation in the treatment process.