I think MDs are the best choice for medications simply because that's basically all they do, day in and day out.

I think it provides a wealth of experience that the good ones can really use to help their patients.

THat's not to say that a general practioner can't do psych meds, of course they can and do - sometimes with very good results. There are protocols for these meds that are implemented in standard general medicine.

Overall though, I would be hesitant to accept these kinds of meds from a GP, but that's just me.