Being given the choice, I would always default to the practitioner with the highest academic credentials. That would mean a psychiatrist (MD or DO, preferably one who specializes in mood disorders) and a PhD psychologist. With these people you have the highest odds of getting someone who knows what they're talking about and has the most experience dealing with patients.

Don't get me wrong, there are some excellent NPs and MSWs out there. I'm not trying to denigrate them and their experience. However in my experience I've had the best results with those with the higher academic credentials. Like anything else, YMMV; there are some lousy people in practice who have the highest credentials, but they're more rare than the alternative on average.