Depression
Depression is a mood disorder that causes a persistent feeling of sadness and loss of interest. Also called major depressive disorder or clinical depression, it affects how one feels, thinks and behaves and can lead to a variety of emotional and physical problems. People may have trouble doing normal day-to-day activities, and sometimes may feel as if life isn't worth living. Depression may require long-term treatment. Most people with depression feel better with medication, psychotherapy or both.