If zyprexa stimulated your appetite & slowed down your metabolism then it could cure the physical aspects of the anorexia. If its truly a thought process on needing to be thin & doing whatever you need to get there...no medication changes that thought process. It takes therapy.
The last time I was in the hospital the dx was anorexia....but my MD said that even cancer patients that fit the definition of the low weight are dx Ed with anorexia....that is different than anorexia nervousa even though medically treated the same....with meds to increase the appetite & usually IV nutrition or feeding tube.
The desire to be thin at all costs can't be fixed with a med....only the symptoms & they hold the hope that a change in thought process will follow. Without good therapy or a good reason the person has for changing their thinking it usually doesn't happen