Endocrine Consequences of Anorexia Nervosa Anorexia nervosa is a perilous disease of unknown etiology that causes a variety of endocrine effects. Characteristic for anorexia nervosa are a reduced food intake and thus significant underweight, as well as the fear of gaining weight. Often sufferers also have a distorted self-perception, the urge to move and amenorrhea. AN is difficult to treat and often has a chronic course, and is associated with an increased mortality risk. The endocrinological changes occur in several endocrine axes, their extent is related to the degree of malnutrition. Low leptin levels, due to the underweight, signal a potentially dangerous lack of energy to the brain. There is a cascade of neuroendocrine adaptive responses to help the organism to survive. The effects of starvation are extensive, affecting the pituitary gland, thyroid gland, as well as the adrenal glands, gonads and bones. In positive cases, most dysfunctions are reversible; the compromised bone stability recovers only slowly.