Anorexia nervosa is an eating disorder that affects up to 4% of women at some point in their lives. It is characterized by an intense fear of gaining weight and results in starvation to be thin. Causes include low self-esteem, distorted body image, media influence, and possible genetic factors. Signs include excessive dieting, weight loss, fatigue, depression, and missed menstrual cycles. Diagnosis involves weight monitoring and history from family. Treatment options range from helplines and local treatment centers to hospitalization, weight gain, and medication.