An Adherence Study of Antipsychotic Medication in Outpatients With Schizophrenia or Schizoaffective Disorder

Inclusion Criteria: 1. Ability to provide written informed consent 2. Male or female, aged from 20 to 65 years 3. Clinician rendered diagnosis of schizophrenia or schizoaffective disorder documented by a checklist of Diagnostic and Statistical Manual of Mental Disorders- Fourth Edition (DSM-IV) criteria 4. Currently taking a single oral antipsychotic (e.g., Quetiapine, Risperidone, Olanzapine, or Amisulpride). 5. Female patients of childbearing potential must be using a reliable method of contraception and have a negative urine human chorionic gonadotropine (HCG) test at enrolment 6. Outpatient status, with psychiatric hospitalization or psychiatric emergency room visit within the previous 2 years and no hospitalizations within 3 months 7. mild to moderate symptom checked by CGI-S (less than score 4) 8. Able to understand and comply with the requirements of the study Exclusion Criteria: 1. Any DSM-IV Axis I disorder not defined in the inclusion criteria 2. Presence of a co-morbid diagnosis that might influence outcome measures (e.g., mental retardation) 3. Alcohol or substance dependence at enrolment (except dependence in full remission, and except for caffeine or nicotine dependence), as defined by DSM-IV criteria 4. Patients who, in the opinion of the investigator, pose an imminent risk of suicide or a danger to self or others 5. Pregnancy or lactation 6. Evidence of hypersensitivity to Quetiapine or other antipsychotics used in the study 7. Use of any cytochrome P450 inhibitors or inducers in the 14 days preceding enrolment 8. Administration of a depot antipsychotic injection within one dosing interval (for the depot) before randomisation 9. use of pillbox 10. Treatment with Clozapine (because of its unique monitoring guidelines) 11. Administration of electroconvulsive therapy (ECT) in the last 6 months 12. Unstable or inadequately treated medical condition such as heart, liver, kidney, or lung disease, or a seizure disorder 13. Involvement in the planning and conduct of the other study. 14. Participation in another drug trial within 4 weeks prior enrolment into this study or longer in accordance with local requirements.