In these cases persons turn to binge-purge strategies as an alternative to starving themselves to achieve their desired weight loss. Thus the bing-purge cycle may occur in both disorders but individuals with anorexia nervosa lose much more weight. Causes of Eating Disorders Anorexia nervosa has been known for over a century but it is only since the early 1970's that bulimia, not associated with anorexia, has been known to professionals. One out of every one hundred women may become anorexic. Estimates of the frequency of bulimia vary from five out of a hundred to twenty out of a hundred in college age women.
Men also develop anorexia nervosa and bulmia but in far smaller numbers.
Both disorders appear to be on the increase. Experts do not know the causes of these disorders nor why they are increasing, but most agree that biological, psychological, and social factors all play a part. Least is known about biological factors. Some evidence suggests that eating disorders may develop as a response to inherited predispositions to mood swings and depression. Other evidence reveals an increased incidence of major depression and alcoholism in blood relatives of persons with bulima or bulimic variations of anorexia nervosa.