Quetiapine Extended Release (XR) for the Management of Psychotic Aggression or Agitation in Adult Acute Psychiatry

Inclusion Criteria: 1. Males or Females aged 18-65 years; 2. Determined by a psychiatrist to be experiencing acute psychotic symptoms (includes mania with psychotic features and drug-induced psychosis); 3. Determined by a psychiatrist to have acted aggressively (score of \> 1 on the OAS); 4. Inpatient status at enrollment; 5. Patient agreement to take oral medication; 6. Provision of written informed consent when considered able to provide consent by the treating team; 7. Female patients of childbearing potential must be using a reliable method of contraception and have a negative urine human chorionic gonadotropin (HCG) test at enrollment. Exclusion Criteria: 1. Pregnancy or lactation; 2. Any DSM-IV Axis I disorder not defined in the inclusion criteria; 3. Patients who, in the opinion of the investigator, pose an imminent risk of suicide or a danger to self or others; 4. Known intolerance or lack of response to quetiapine fumarate or any other atypical psychotics, as judged by the investigator; 5. Use of any of the following cytochrome P450 3A4 inhibitors in the 14 days preceding enrolment including but not limited to: ketoconazole, itraconazole, fluconazole, erythromycin, clarithromycin, troleandomycin, indinavir, nelfinavir, ritonavir, fluvoxamine and saquinavir; 6. Use of any of the following cytochrome P450 inducers in the 14 days preceding enrolment including but not limited to: phenytoin, carbamazepine, barbiturates, rifampin, St. John's Wort, and glucocorticoids; 7. Administration of a depot antipsychotic injection within one dosing interval (for the depot) prior to being recruited for the trial; 8. Patients receiving treatment with an antipsychotic other than Seroquel XR (either IM or oral) within one dosing interval prior to being recruited for the trial; 9. Patients receiving treatment with mood stabiliser or anti-depressant medication within 7 days prior to treatment with Seroquel XR; 10. Substance or alcohol abuse or dependence at enrolment (except dependence in full remission, and except for caffeine or nicotine dependence), as defined by DSM-IV criteria; 11. Medical conditions that would affect absorption, distribution, metabolism, or excretion of study treatment; 12. Unstable or inadequately treated renal, hepatic, cardiovascular, respiratory, cerebrovascular, or other serious progressive physical disease as judged by the investigator; 13. Involvement in the planning and conduct of the study; 14. Previous enrolment in the present study; 15. Participation in another drug trial within 4 weeks prior enrolment into this study or longer in accordance with local requirements; 16. A patient with Diabetes Mellitus (DM) fulfilling one of the following criteria: * Unstable DM defined as enrolment glycosylated hemoglobin (HbA1c) \>8.5%; * Admitted to hospital for treatment of DM or DM related illness in past 12 weeks; * Not under physician care for DM; * Physician responsible for patient's DM care has not indicated that patient's DM is controlled; * Physician responsible for patient's DM care has not approved patient's participation in the study; * Has not been on the same dose of oral hypoglycaemic drug(s) and/or diet for the 4 weeks prior to randomisation. For thiazolidinediones (glitazones) this period should not be less than 8 Weeks; * Taking insulin whose daily dose on one occasion in the past 4 weeks has been more than 10% above or below their mean dose in the preceding 4 weeks. 17. An absolute neutrophil count (ANC) of \> 1.5 x 109 per liter; 18. Refusal to take oral medication and intramuscular antipsychotic medication is administered instead.