i was on Abilify and had a terrible time with it. i have found for bi-polar Lamictal (300mg) works best for me. it has had NO effect at all on my A1c, nor have i gained or lost any weight on it. in fact, i have had NO side effects at all from it and it REALLY helps tremendously.
good luck to you. its another hard disease to deal w/ particularly b/c all the anti-psychotics elevate BGs. i take a strong anti-psychotic for my schizophrenia called Clozapine, and its the only one i have ever taken that doesn't raise my BGs or effect my A1c level.