I have been on Seroquel and yes, the first few nights can hit you like a train but after a while the sedative effect passes and it just keeps you chilled. Apart from the tiredness there were few other side-effects (one can be restless legs)so it is worth giving it a go. It helped a bit with agitation and restlessness but in the end I found Olanzapine to be a better fit for me. Still, if i am having trouble sleeping I use 25mg of Seroquel and sleep like a baby as I don't use it every night.