Anorexia nervosa is an eating disorder defined by persistent restriction of energy intake, intense fear of gaining weight, and a distorted perception of body shape or weight. The result is significantly low body weight for the person’s age, sex, and developmental stage.

The disorder typically begins in adolescence or early adulthood and is more common in females, though males are also affected. Behavioral signs include extreme dieting, excessive exercise, and sometimes purging. Medical complications can be severe: bradycardia, osteoporosis, electrolyte imbalance, and in extreme cases multi-organ failure. Psychological features often include perfectionism, anxiety, and a sense of control obtained through food restriction.

Causes are multifactorial—genetic predisposition, cultural pressure toward thinness, family dynamics, and individual temperament all contribute. Treatment requires a combination of medical stabilization, nutritional rehabilitation, and psychotherapy. Family-based treatment has strong evidence for adolescents; adult treatment is more variable in outcome. Early intervention improves prognosis, yet recovery can be prolonged and relapse is a recognized risk.

Anorexia is not a lifestyle choice. It is a serious mental illness that requires specialized care.