I have taken Zyprexa before (can't remember the dose - too long ago) and it made me sleep for 12 to 14 hours per day. I can't say anything about the weight gain because I wasn't on it long enough to notice, but one of my cousins who has bipolar takes Zyprexa - a small dose - and has responded well to it. Any side effects that you experience can be discussed with your doctor. Good luck!