You may be depressed if you have experienced at least five of the following symptoms most of the day, nearly every day, for at least 2 weeks.
People who are depressed have at least one of the first two symptoms.
Most people experience some form of depression at some point in their lives. Depression can range from a minor problem to a major, life-threatening illness. Depression is usually treatable. For many people, treatment can dramatically improve their quality of life.
WebMD Medical Reference from Healthwise