mCPP is the main metabolite of trazodone, an antidepressant I took for quite a while. I never experiences anything remotely psychedelic from it.
I've tried it a couple of times and there's nothing psychedelic about it at all. My vision was slightly altered but not in a psychedelic way, and it wasn't anything resembling mind-expanding. Really dirty drug.
I don't think there is any research into its health benefits.