Major depressive disorder is also known as major depression, clinical depression, or unipolar depression. The term unipolar refers to the presence of one pole, or one extreme of mood- depressed mood. Different people are affected in different ways by major depression.
Some people have trouble sleeping, they lose weight, and they generally feel agitated and irritable.
Others may sleep and eat too much and continuously feel worthless and guilty. There is no one way that people look and behave when they have major depression. However, most people will either have depressed mood or a general loss of interest in activities they once enjoyed, or a combination of both. In addition they will have other physical and mental symptoms that may include fatigue, difficulty with concentration and memory, feelings of hopelessness and helplessness, headaches, body aches, and thoughts of suicide. In adults, major depressive disorder affects twice as many women as men.