Quetiapine Augmentation for Primary Anxiety Disorder or Mood Disorders With Co-morbid Anxiety Symptoms

Inclusion Criteria: * Provision of written informed consent * A diagnosis of primary anxiety disorder or mood disorder with co-morbid anxiety symptoms by Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) * A 14-item Hamilton Anxiety Scale (HAM-A)\>= 14 * Subject have received single antidepressant at a therapeutic dose for at least 6 weeks * Male or female aged 18-65 years * 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 * Able to understand and comply with the requirements of the study and sign informed consent Exclusion Criteria: * Pregnancy or lactation * Any DSM-IV Axis I disorder not defined in the inclusion criteria. * Receiving any anti-psychotic 7 days prior to entering the study * Patients who, in the opinion of the investigator, post an imminent risk of suicide or a danger to self or others * Known intolerance or lack of response to quetiapine fumarate, as judged by the investigator * Use of any of the following cytochrome P450 3A4 inhibitors in the 14 days preceding enrollment including but not limited to: ketoconazole, itraconazole, fluconazole, erythromycin, clarithromycin, troleandomycin, indinavir, nelfinavir, ritonavir, fluvoxamine and saquinavir * Use of any of the following cytochrome P450 3A4 inducers in the 14 days preceding enrollment including but not limited to: phenytoin, carbamazepine, barbiturates, rifampin, St.John's Wort, and glucocorticoids * Administration of a depot antipsychotic injection within one dosing interval (for the depot) before randomization * Substance or alcohol dependence at enrollment (except dependence in full remission, and except for caffeine or nicotine dependence), as defined by DSM-IV criteria * Opiates, amphetamine, barbiturate, cocaine, cannabis, or hallucinogen abuse by DSM-IV criteria within 4 weeks prior to enrollment * Medical conditions that would affect absorption, distribution, metabolism, or excretion of study treatment * Unstable or inadequately treated medical illness (e.g. congestive heart failures, angina pectoris, hypertension) as judged by the investigator * Involvement in the planning and conduct of the study * Previous enrollment or randomization of treatment in the present study * Participation in another drug trial within 4 weeks prior enrollment into this study or longer in accordance with local requirements * A patient with Diabetes Mellitus (DM) fulfilling one of the following criteria: * Unstable DM defined as enrollment 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 randomization. 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 * An absolute neutrophil count (ANC) of \<= 1.5x10(9) per liter