This debate has been going on for a while and will probably go on for a very long time. I have always been amazed that antidepressants are a billion dollar industry when even the creators don't actually know how they work or what really causes depression. If you pay attention in the commercials, wether it's a happy person running on a beach or a sad cartoon stick figure, at some point they always mention how the drug is thought to work in the brain.

Clip of a 60 minute interview where Dr. Irving Kirsch discusses his studies where he has come to believe that antidepressants don't work because of the chemicals in them but rather because of a placebo effect where the patient thinks they're being given a fix so it works.
http://www.cbsnews.com/video/watch/?id= ... .galleries

The transcripts for the full interview
http://www.cbsnews.com/8301-18560_162-5 ... bsCarousel

so you can fail as much as you'd like just as long as you hit 2 at some point-
"To approve any drug, the Food and Drug Administration merely requires that companies show their pill is more effective than a placebo in two clinical trials - even if many other drug trials failed."

Due to similar studies Great Britain has decided to change methods-
"Because of the review, new public health guidelines were issued. Now drugs are given only to the severely depressed as the first line of treatment. For those with mild to moderate depression, the British government is spending nearly half a billion dollars training an army of talk therapists."

Interesting article, long read though.
The New Yorker- HEAD CASE Can psychiatry be a science?
http://www.newyorker.com/arts/critics/a ... rge_menand