Eligibility Criteria:
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