Could antidepressants really work?

Yes. I don't agree with the last answer. Antidepressant medications can have a major impact on depressive disorders. Some people will require psychotropic medications for recovery.
Yes. but disputed. According to Kirsch, the mean differences between the antidep. & placebo were small, the differences were in favor of the drugs & they were statistically significant. What this means is that the drug did appear to have some effect on mood proven by the data. This small difference accounted for in 2 ways:1- the active drug actually has an effect, 2- that their is also a placebo effect. .