Answer:
Sadness is a human emotion that all people feel at certain times during their lives. Feeling sad is a natural reaction to situations that cause emotional upset or pain. There are varying degrees of sadness. But like other emotions, sadness is temporary and fades with time. In this way, sadness differs from depression.
Depression is a longer-term mental illness. It impairs social, occupational, and other important areas of functioning. Left untreated, symptoms of depression may last for a long time.
Yes, any age can have depression.