Doctor Grohol has written an excellent primer on depression here: http://psychcentral.com/disorders/depression/

This subsection is one I particularly appreciate: Causes of Depression

HelpGuide.org is another resource I have found helpful. I liked this article entitled, Helping a Depressed Person: TAKING CARE OF YOURSELF WHILE SUPPORTING A LOVED ONE. http://www.helpguide.org/mental/livi...sed_person.htm