Efficacy and Safety of Quetiapine Fumarate Sustained Release (SEROQUEL SR) in the Treatment of Major Depressive Disorders

Inclusion Criteria: * Patient is able to provide written informed consent before beginning any study related procedures * Patient has a documented clinical diagnosis of major depressive disorder * Patient is able to understand and comply with the requirements of the study, as judged by a study investigator Exclusion Criteria: * Patients with a history of non-compliance as judged by the study investigator * Patients with a known lack of response to previous treatment with quetiapine * Patients who have participated in a clinical trial within 4 weeks of randomization