It is incredibly frustrating that you say this, even while quoting the DSM which says:
i) at least 2 weeks
ii) and at least five of the following symptoms
iii) clinically significant impairment in social, work, or other important areas of functioning almost every day.
These symptoms are not vague. Unless you take one symptom, and ignore the significant impairment clause.
Of course they are. And there's a lot of variability in diagnosis between practitioners. Some even say that depression isn't really a disease at all.
There is an excellent book on this topic that I cannot recommend highly enough:
Title: "Manufacturing Depression: The Secret History of a Modern Disease"
Quote: (about Congitive-behavioral therapy) “a method of indoctrination into the pieties of American optimism, an ideology as much as a medical treatment.”
Here's a discussion of the book (and topic) at the New Yorker entitled "Head Case": http://www.newyorker.com/arts/critics/atlarge/2010/03/01/100...