I would listen to your psych doc. They know more about that field then your regular doctor. If you are really worried then call your psych doc and ask them. I am pretty sure you can take them together because you have to have the weaning process from the other drug and be able to start the other.
I would talk to your psych doc and tell him what your regular doctor told you and see what he says at that point. After that, I would personally go with whatever he says since he may understand the drugs more than your regular doctor does.