This isn't my advice but when I stopped it cold (twice) I didn't have any problems. I switched to Latuda which probably has no bearing on the subject. At the time, though, I was taking a medium high dose of Seroquel, using it for an antipsychotic,, and it didn't make me sleepy. On the other hand I really don't want to quit my current 50mg because it helps me sleep so well at that dose. Maybe insomnia would be a side effect of quitting it?

Just the same, tapering off is always a good precaution.