Seroquel for Sleep Healthcare providers may prescribe Seroquel for sleep. However, the medication is not approved for this use, nor is it an appropriate use. While it does cause drowsiness and may help with insomnia, it also carries the risk of serious side effects. If your healthcare provider is prescribing Seroquel for sleep, you may want to have an honest discussion, asking if he or she believes that you may have a mental illness.