I agree with everything bluebicycle wrote. I've heard plenty of people say they gained little or no weight from either, and plenty who have, even extreme amounts. I think people should be open to trying these medications, if recommended by their psychiatrists. I hear many accounts of both being very effective for bipolar disorder. Both have been for me.

I only took Zyprexa for a few months maybe 11 years ago. I did gain some weight from it fairly quickly, but the psychiatrist and I both agreed it made a huge difference in my moods, quickly. It, unfortunately, also gave me akathisia. For those reasons, we moved on to other options.

Seroquel has also been effective for me. I found regular Seroquel less weight friendly for me than Seroquel XR (extended release). For the most part, Seroquel XR has been weight neutral for me at doses of around 450 or 500 mg or less. Higher doses do seem to increase my appetite to various degrees. Both Seroquels required time to adjust to the sedation. That wait can seem too long for some people. Perhaps some don't have excess sedation. Nowadays, Seroquel XR helps me sleep, but no longer over sedates me. The time I take it and the time I fall asleep helps.