Eating disorders, one of the most difficult mental illnesses to diagnose and cure, are divided into three categories: anorexia nervosa, bulimia nervosa, and binge eating. Frequently, sufferers flatly deny they have a problem, and treatment by doctors and psychiatrists produces little success. There appears to be a connection between anorexia and bulimia, and affective disorders (depression). Thus, antidepressants are often used in treating eating disorders. In February 1998, researchers identified a pair of hormones which influence eating habits in rats. These hormones--orexin A and orexin B, bind to two receptors in the lateral hypothalamus, the region of the brain believed to regulate appetite. Whether these hormones produce a similar activity in humans is yet unknown; however, researchers appear optimistic that the development of drugs imitating these hormones may aid in the treatment of eating disorders by stimulating or depressing appetite.

The psychological driving force behind anorexia...