Current substance abuse or history of substance dependence in the past 6 months

Use of depot antipsychotics in the past 6 months

History of epilepsy, head trauma, stroke or other serious medical or neurological illness

Bipolar depression, schizophrenia or other psychotic disorder

Moderate-severe suicidal risks

Severe cognitive impairment

Initiating or stopping formal psychotherapy within six weeks prior to enrollment

A history of poor response to SSRIs or other antidepressants

A history of previously received electroconvulsive therapy

A history of severe adverse reaction to SSRIs or other antidepressants

Inability to follow protocol

NMDA Modulation in Major Depressive Disorder in Late- Life