Anorexia is an eating disorder where people starve themselves to lose weight despite being skinny and convinced they are overweight due to an intense fear of becoming fat. It is most common in teens and women who want to be perfect and can be caused by a fear of being fat, a desire for control and perfection, and cultural pressures from modeling, dancing and some sports. Symptoms include irregular periods and heartbeats, brittle skin, shortness of breath, anxiety, weakness and a refusal to eat despite feeling hungry. Diagnosis involves denial of being underweight, constant exercising, and baggy clothes, while treatment begins with willingness to change and may involve counseling, hospitalization, or antidepressants.