I'm on heavy medications for schizoaffective bipolar type I gained loads of weight on olanzapine despite barely eating so switched to haloperidol but still it's stopped weight gain but can't lose it so thinking of switching mirtazapine to paroxetine I have been on it before it worked well for me and yes I'm aware of the terrible withdrawals just wanted experiences I've tried sertraline and citalopram neither worked for me only anti depressants that have worked is mirtazapine paroxetine and trazodone but I believe mirtazapine and trazodone both cause weight gain.