Actually, and again forgive me if I'm wrong, but it seems to me that we're being messed with on this thread. Hallucinations generally don't just pop up out of the blue. I didn't wake up one day seeing ghosts, it grew on me. I'd see shadows, hear footsteps, snatches of voices, and over months they got more concrete. So, if someone "suddenly" woke up on morning seeing aliens then they'd probably have something completely different from a schizophrenic spectrum disorder. Delirium or substance abuse seems most likely, though some form of sleep paralysis or epilepsy is also a possibility.
Also, if the poster woke up one day with said delusions, and posted them on the forum, he/she is a very fortunate person to have seen a doctor in one day who would prescribe him a strong drug like seroquel. You have to titrate gradually upwards on seroquel, and it's not immediately effective. So the cure seems as "sudden" and unlikely as the "sudden" aliens.
So, what doctor, based on a case history of a patient seeing one off aliens, would on the same or following day as the hallucination prescribe a strong antipsychotic, instead of taking time to make a proper diagnoses? And how would that anti psychotic work so quickly?
You can see why I'm dubious... but I do apologise if in some way I've misunderstood what's happening here.