The following link is to the following article, that evaluates the (lack of) effectiveness of antidepressants:
Pigott, H.E., Leventhal, A.M., Alter, G.S., and Boran, J.J. (2010) Efficacy and Effectiveness of Antidepressants: Current Status of Research. Psychotherapy and Psychosomatics (79) 267-279.
Antidepressants are not significantly better than placebo, and have significant side effects.