Hi, I have the same problem with 600mg Seroquel XR (2 years) and 100mg regular Seroquel (12 years). Can't wait to see my psychiatrist. When I sleep, it's like if I am under hypnosis, not totally asleep. Until my next visit, I've searched to see if this medication can stop working after a few years and found no valid information yet. I feel as if I'm wasting precious time; summer is almost here and I'd love to enjoy the sun, not the moon...