MAJOR INCLUSION CRITERIA:

1. Must experience sleep disturbances at least 3 nights/week, based on historical data
2. Must meet the diagnostic requirements for Major Depressive Disorder
3. Must have QIDS-SR16 score between 6 and 15
4. Must be either newly diagnosed or show symptoms of relapse/recurrence of depression while not on medication
5. Age 21-64, inclusive
6. Women must use a medically acceptable form of contraception (steroidal contraceptive, double-barrier, or intra-uterine device) during the entire study period, or: be surgically sterilized, post-menopausal, agree to use double-barrier contraception throughout the study period, or must have a negative urine pregnancy test prior to randomization.
7. Subject must be stabilized on all ongoing long-term medication therapy for at least 28 days prior to screening visit.

MAJOR EXCLUSION CRITERIA:

1. Severity of depressive episode had been rated as "severe" or "severe with psychotic features."
2. History of a suicide attempt or suicidal ideation.
3. History of mania, manic episode or bipolar disease.
4. Currently using a benzodiazepine or SSRI or more than 2 days of use within the 28 days preceding randomization.
5. Use of prescription and non-prescription sedative drugs given for the purpose of sleep induction or to relieve jet lag
6. Any abnormal pre-study laboratory values that require clinical intervention
7. Prior failure to respond to escitalopram therapy for depression
8. Current depressive episode requiring inpatient hospitalization.
9. Shift work or requirement for a regular change in sleep schedule by at least six hours within the previous 28 days.
10. History of drug addiction, alcoholism, or drug abuse.
11. A positive urine drug screen for medication that would interfere with the assessment of the study medication.
12. Known allergy to zolpidem, escitalopram or any of their excipients
13. History of sleep apnea
14. History of myasthenia gravis
15. The presence of any untreated or uncompensated clinically significant renal, endocrine, gastrointestinal, hepatic, respiratory, cardiovascular, other neurologic, hematologic, oncologic, immunologic, cerebrovascular disease or malignancy.
16. Pregnant or breastfeeding
17. Subject is participating in another clinical trial, or has completed another clinical trial within 28 days prior to screening.