Help please! what drugs are used to treat major depression and how do they work?

Different types: There are different categories of antidepressants based on the chemicals they affect in the brain. Ssri's work on serotonin - zoloft, prozac, paxil, lexapro, celexa. Snri's like effexor, Pristiq (desvenlafaxine) and Cymbalta work on both serotonin and norepinephrine. Wellbutrin works on Dopamine levels. See this link for a complete list http://www.Mayoclinic.Com/health/antidepressants/hq01069.

Most common: There are many antidepressants. SSRI's are the most common and they allow the brain to absorb more serotonin to help with depressive symptoms.