The evolutionary origin of depression(economist.com)
economist.com
The evolutionary origin of depression
http://www.economist.com/sciencetechnology/PrinterFriendly.cfm?story_id=13899022
http://www.economist.com/sciencetechnology/PrinterFriendly.cfm?story_id=13899022
http://news.ycombinator.com/item?id=677381
It got 63 comments, so it might be worth reading it there.