I was only taking 100mg just over a year but was gaining way too much weight so my psychiatrist pulled me off it. I did 4 weeks down to 50mg then off but went onto a TCA, Doxepin. Did have withdrawal but it didn't last long. Because I have sleepers, I can't really tell you if insomnia becomes a problem once discontinuing Quetiapine. Hope all goes smoothly for you x