Major depressive disorder represents the classic condition in the mood disorders group. Depression is characterized by discrete episodes of at least two weeks duration and causes a persistent feeling of sadness and loss of interest. It affects how you feel, think and behave and can lead to a variety of emotional and physical problems. You may have trouble doing normal day-to-day activities, and sometimes you may feel as if life isn't worth living.
A more chronic form of depression, persistent depressive disorder (dysthymia), can be diagnosed when the mood disturbance continues for at least 2 years in adults or 1 year in children.
For a diagnose of major depressive disorder five or more of the following symptoms have been present during the same two weeks period; at least one of the symptoms is either depress mood or loss of pleasure or interest.Depression symptom can include: