I went cold turkey off Seroquel XR without my pdoc knowing. Felt dizzy, had loss of balance, developed severe depression, couldn't sleep, and vomited a bunch of times. I had to go back on it immediately (which was hard because I was vomiting).

I told my pdoc about this and we developed a taper plan. I didn't like his taper plan, though. One of his steps was going directly from 250mg to 50mg overnight. Well, I vomited again doing that too. So instead, I went down by 50mg every week and was fine.

It wasn't ideal to go down by 50mg every week (because it took foreverrrr), and my pdoc said I didn't have to go that slow, but it prevented me from vomiting, so I was ok with that.

The insomnia was only there for about 2 weeks after stopping it, but I guess it depends on how long you've been on it. I was only on it for like 6 months.