"which antidepressant is the most effective?"  Interestingly, all of the antidepressants have roughly the same level of efficacy.  In other words, if you take 100 random patients and put them on any one of the antidepressants, you will see roughly the same percent of patients have a response, and the same percent have a full remission.  The answer, therefore, is that all antidepressants are equally effective, at least until you try them.