SAD is more common type of depression that cans a patient face. A person who faces a depression illness in winter season when the duration of dark hours are more than the sunlight hours might have SAD. The symptoms of SAD go away in spring and summer seasons. These patients normally treated by the light therapy. They sit in front of special light. This type of therapy effective for almost half of all the patients, and some patients needs to Anti- depression medicines or Psychotherapy or both.