seroquel is low potency. it could easily take 400mgs to get the job done...zyprexa is higher potency, so it might only take 15 or 20mgs.

zyprexa can cause weight gain and diabetes, plus all the usual stuff with tranquilizers (depression, tardive dyskinesia, twitches, etc.). seroquel has a low rate of akathisia and muscle twitches, but it can still cause tardive dyskinesia.