Seroquel is a strong antipsychotic agent. While it does cause drowsiness, using it for sleep alone could bring along unwanted side effects or even new medical conditions. Using a medicine specifically prescribed as a sleep aid would be a better option than exploiting a side effect of seroquel. Also, patients who currently take seroquel often feel drowsy throughout the entire day. Discuss any concerns you may have with your doctor, and he/she will work with you to find a regimen that works best for you.