Serotonin
Depression
Information about this certain type of depression. http://www.apollolight.com/new_content/circadian%20rhythms_disorders/depression/serotonin_depression.html
Serotonin & Depression
Information about Serotonin. http://serendip.brynmawr.edu/bb/neuro/neuro99/web3/Ho.html
Psychology
today
Article about serotonin and its relation to depression. http://www.psychologytoday.com/articles/pto-525.html