Depression is a common experience that affects both physical and mental health. The word depression is often used for feelings of sadness from time to time, such as during fights with a loved one or being ignored by a friend. Life can often become full on when dealing with combinations of stress, disappointment, or grief, and it can be common to experience feelings of sadness, which may occur without any apparent reason. However, the persistence of these feelings for a period of 2-weeks or more may suggest that these feelings of sadness have become and illness.