While searching Google for info on the chemical link to depression, I found this site: http://www.clinical-depression.co.uk And no, I'm not promoting what they're selling on the site. They have this free section called "The Learning Path" with a lot of really good information. If you read at least one thing on that site, read the sections under "Understanding Depression." There is some amazing advice there; it was like the site was talking directly to me. Check it.