Aetna Intelihealth
Aetna: Inteli Health: Major Depression
Thorough overview of major depression. Includes information on symptoms, diagnosis, treatment, and much more.
WebMD
Web Md: Depression Guide
This site from WebMD Health provides great information on depression. Includes a section on the facts of depression, types of depression, causes, diagnosis, treatment options, care giving, and different populations information.
Other
Psychotherapy Versus Medication for Depression
An research study (1995) from doctors specializing in depression treatment that discusses the differences between psychotheraphy and medication.
The National Alliance on Mental Illness
National Alliance on Mental Illness: Depression
This site is a concise page from NAMI describing depression, its causes and symptoms, statistics, treatment, and more.