The Etiology of Anorexia Nervosa

T he valid question in a discussion on the etiology of anorexia nervosa is: what caused the willful starvation that stems from the fear of fatness? It is thus important to clarify two fundamental issues at the outset: First, starvation is the cause of many of the features of anorexia nervosa, such as amenorrhea; constipation; insomnia; preoccupation with food, dieting, and shape; bulimia; food fads; increased consumption of coffee, tea, and chewing gum; and diminished sexual desire [1,2]. To suggest, for instance, that a fear of sexuality is the cause of amenorrhea or that a need to withhold is the cause of constipation is absurd. Second, the cardinal feature of anorexia nervosa is a fear of fatness, or a pursuit of thinness. The food avoidance and the vomiting and purging stem from this fear. The disorder is not due to a loss of appetite (anorexia) or a primary fear of eating or food. Thus, for instance, to postulate a link between anorexia nervosa and Crohn's Disease is absurd, because in the latter condition there is a true loss of appetite. There are currently seven main theories organized along different conceptual levels that attempt to explain the etiology of anorexia nervosa. Logically, they are not mutually exclusive, and they overlap to some degree. However, their explanatory power varies and so does the strength of the evidence for each theory. This review will discuss each theory.