Effects of Seroquel XR on Sleep Architecture in Patients With Major Depressive Disorder

Patient Inclusion Criteria: * Men and women aged between 20 and 65 * Diagnosis of major depressive disorder as assessed by Structured Clinical Interview for DSM-IV (SCID-IV) * A score of 1 or greater on any of the sleep items (items 4, 5, 6) from the Hamilton Depression Rating Scale (HDRS) * Provision of written informed consent Healthy Control Subject Inclusion Criteria: * Healthy Men and Women aged between 20 and 65 * Provision of written informed consent Exclusion Criteria: * Presence of any major physical or neurological illness (e.g.，head trauma， epilepsy，seizure，stroke，cerebral tumor，multiple sclerosis，cerebrovascular disease, narrow-angle glaucoma, drug hypersensitivity，etc.) * Diagnosis of any Axis I disorder other than major depressive disorder or presence of symptoms requiring hospitalization * Drug abuse in past 3 months * Women who are pregnant，breastfeeding, or planning pregnancy * Contraindications to drugs used in the study (e.g., allergy, intolerance, etc.) * Unstable medical illness or severe abnormality in laboratory test at screening assessment * Increase in blood glucose, lipid, and calcium levels at screening * Low blood pressure at screening assessment * Intelligence quotient below 80 * 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 * Use of any of the following cytochrome P450 3A4 inducers in the 14 days preceding enrolment 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 randomisation * Substance or alcohol dependence at enrolment (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 3 months prior to enrolment * Previous enrolment or randomisation of treatment in the present study. * Participation in another drug trial within 4 weeks prior enrolment into this study or longer in accordance with local requirements * Medical conditions that would affect absorption, distribution, metabolism, or excretion of study treatment * A patient with Diabetes Mellitus * An absolute neutrophil count (ANC) of \<= 1.5 x 10\^9 per liter * Insomnia from other causes of medical or neurological diseases * Involvement in the planning and conduct of the study