Difference between clinical depression and sadness

Although depression is often thought of a being an extreme state of sadness, there is a vast difference between clinical depression and sadness.
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Experiencing Sadness is a part of being human, a natural reaction to painful circumstances. All of us will experience sadness at some point in our lives.

Depression, however, is a physical illness with many more symptoms than an unhappy mood. The person with clinical depression finds that there is not always a logical reason for his dark feelings.

Sadness is a feeling that passes as a person comes to term with his troubles. Depression can linger for weeks, months or even years.