Antidepressants act in 2-8 weeks depending on the severity of symptoms and nature of antidepressants. There is no best or worst antidepressant. The choice Is made by the psychiatrist after getting know the patients condition after a detailed evaluation. There are many many protocols used worldwide for treatment of depression. If that alone determines the treatment, physicians are not necessary at all. Usage of antidepressants is an art, masters by knowledge, expertise and Clinical acumen. Good luck

Any antidepressant will take 2 weeks for its action so be calm and trust the process

It's purely depends on your symptoms and how the they responds to treatment.

It varies from patient to patient, but atleast it is to be taken for 6 months