"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. If you have been experiencing some of the following signs and symptoms most of the day, nearly every day, for at least two weeks, you may be suffering from depression: Persistent sad, anxious, or empty mood Feelings of hopelessness, or pessimism Irritability Feelings of guilt, worthlessness, or helplessness Loss of interest or pleasure in hobbies and activities Decreased energy or fatigue Learn more about depression and make your doctor notes. Read how you can know if you have a depression by doing your own depression test."