I take lamictal and zyprexa. Zyprexa is extremely good at controlling my psychosis but I have had significant weight gain (40 lbs). Lamictal works well too. I think my dosage needs to be tweaked because I've been feeling very low but I'm also on a low dosage (100 Mgs). I've taken metformin in the past for insulin resistance and it have me diarrhea (tmi) every time I took it. I've never taken it to control weight gain but I'm going to ask my pnp about it since I'll be going back on zyprexa.