The most common side effect is sedation, and is prescribed specifically for this effect in patients with sleep disorders. Seroquel will put the patient into a drowsy state, and will help the patient fall asleep. It is one of the most sedating of all anti psychotic drugs, rivaling even the most sedating older antipsychotics. Many prescriptions call for the entire dose to be taken before bedtime because of its sedative effects. Although quetiapine is approved by the FDA for the treatment of schizophrenia and bipolar disorder, it is frequently prescribed for off-label purposes including insomnia or the treatment of anxiety disorders. Due to its sedative side effects, reports of quetiapine abuse (sometimes by insufflating crushed tablets) have emerged in medical literature; Quetiapine belongs to a series of neuroleptics known as atypical antipsychotics, which have become increasingly popular alternatives to typical antipsychotics such as haloperidol. Quetiapine HAS approvals for the treatment of schizophrenia and acute mania in bipolar disorder. It is also used off-label to treat other disorders, such as post-traumatic stress disorder, alcoholism, obsessive compulsive disorder, anxiety disorders, hallucinations in Parkinson's disease patients using ropinirole, and as a sedative for those with sleep disorders. The most common side effect is sedation, and is prescribed specifically for this effect in patients with sleep disorders. Seroquel will put the patient into a drowsy state, and will help the patient fall asleep. It is one of the most sedating of all anti psychotic drugs, rivaling even the most sedating older antipsychotics. Many prescriptions call for the entire dose to be taken before bedtime because of its sedative effects. Although quetiapine is approved by the FDA for the treatment of schizophrenia and bipolar disorder, it is frequently prescribed for off-label purposes including insomnia or the treatment of anxiety disorders. Due to its sedative side effects, reports of quetiapine abuse (sometimes by insufflating crushed tablets) have emerged in medical literature; for the same reason, abuse of other antipsychotics, such as chlorpromazine (Thorazine), may occur as well, but research related to the abuse of typical antipsychotics is limited. for the same reason, abuse of other antipsychotics, such as chlorpromazine (Thorazine), may occur as well, but research related to the abuse of typical antipsychotics is limited.