excellent topic and article. I am blessed that I only had a problem once and this was called menopause :) but my closest one suffers and I feel so helpless. Yes, in the old days it was different because I don't even remember using the word as much. We just had bad days.
To feel sadness is nothing wrong and so important to appreciate the following euphoria. Its a natural process of life.
Depression seems to be triggered by a chemical imbalance and therefore so vicious.