For the symptom, see Anorexia
Anorexia nervosa is an eating disorder that results in very low body mass. Body mass becomes so low that the body can no longer maintain a proper balance of blood and electrolyte chemistry, which often results in heart disease and cardiac arrest, along with other complications such as malnutrition. The disorder is almost always seen in women, although it is becoming more common in men. Nervosa patients perceive themselves as obese even as their weight continues to fall.
Nervosa is extremely difficult to treat, even in hospital settings. In addition to psychiatric involvement, the patient will often require a high-calorie diet which they inevitably resist.
The term anorexia is also used to describe eating disorders related to stomach or intestinal pain that result from eating. However, these types of disorder will disappear when the underlying cause is treated.
See also Bulimia, another eating disorder characterized by binge and purge eating.