Depression, The Misunderstood Epidemic - Full Depression Documentarybr CLICK ► [] to try The End Your Depression System.br br Depression (major depressive disorder or clinical depression) is a common but serious mood disorder. It causes severe symptoms that affect how you feel, think, and handle daily activities, such as sleeping, eating, or working. To be diagnosed with depression, the symptoms must be present for at least two weeks. Some forms of depression, like bipolar disorder, are slightly different, or they may develop under unique circumstances.