I had DM before I was ever put on anti-psychotics. I'm on metformin, just one 500 mg tab per day, and it's kept my blood sugars down very well. I have also been able to go off of it when I lose weight, although I don't think it'll happen that way again as I am getting nothing but older. Honestly, I don't think Zyprexa has made it worse. But maybe I'm just lucky.