Anorexia nervosa is a serious mental disorder, mainly affecting women. Levels of disability and mortality are high. It typically starts peri-pubertally, i.e. at a developmentally sensitive time. Many sufferers have anxious, perfectionist and obsessional traits. Self-starvation and extreme thinness become rewarding to sufferers, whereas food, eating and normal body size are feared. Early intervention is essential: psychological therapies and/or skilled refeeding in hospital (in severe cases) are the treatments of choice. With family-based treatment, 60–80% of adolescents with anorexia nervosa recover, whereas only 20–30% of adults who have a more enduring form of the illness recover with best available treatments.