I was on Rexulti for two months, I noticed no weight gain, in fact I actually lost weight while on it. The side effects were minimal, it did make me more awake and disrupt my sleep so I took it in the morning instead of in the evening. As far as effectiveness goes I can't speak on that as I have schizoaffective disorder, depressive type. It was not effective in managing my symptoms so I switched to something else.