I take 25 mg of Seroquel (I used to take a very high dose for mania, but now I take Abilify for that). Even at that small dose, it's very very sedating and I go to bed extremely early on work nights (I usually get into bed at around 6pm, though it might take an hour or so to get to sleep, but when I do, I quite literally pass out). I need about 10 hours of sleep with the Seroquel. It's very very effective for sleep, but I would not take it unless you're able to get a great deal of sleep; at least that's been my experience with it.