Major depressive disorder (MDD) is one of the most common psychiatric disorders with serious socioeconomic consequences on daily life and health care costs. Despite the advent of newer antidepressants that target monoamine pathways, nearly 50% of patients have no response to first-line antidepressant therapy. Thus, a combination of medications with different strategies at the beginning of treatment could provide further therapeutic benefits to MDD patients

Inclusion Criteria:

1. Patients with age greater than 18 years old.
2. Patients with Ham-D score at least 18 with item 1 depressed mood scored 2 or greater are eligible.

Exclusion Criteria:

1. Patients with bipolar I or bipolar II disorder; eating disorders, personality disorders, and mental retardation, current diagnosis anxiety disorders (except for specific phobia), mental disorder due to general medical condition; met criteria for substance dependence or abuse in the previous three months; have a concurrent medical illness or history of seizures that would contraindicate use of the study medication and are receiving Electroconvulsive therapy (ECT).
2. Pregnant women or women not using medically accepted means of birth control are excluded.
3. Persons who score greater than 2 on the suicide item of the Ham-D, or who are judged to have significant suicidal ideation or potential in the view of an investigator, are excluded.
4. Patients who are required to be free of all psychotropic except for escitalopram and anti-inflammatory medications for at least four weeks before study entry.