I was put on metformin years ago for weight gain I experienced from gaining over a 100 lbs from Zyprexa. It kept me from developing full blown diabetes....but I did develop insulin resistance.....no brainer.....I was 248 lbs....the metformin got me down to 210....at least some....but Zyprexa is viscous about stopping your metabolism..so even the smallest food doesn't get burned off.
I since stopped Zyprexa....the withdrawals were horrendous.....medical marijuana helped alot. I've lost 31 lbs in 2 most and feel awesome. I'm not on any antipsychotic..just a mood stabilizer that doesn't cause weight gain. Stay clear from the atypical antipsychotics...they will destroy your health in the long run.