In this study the investigators use clinical, biological and imaging markers to develop predictive markers for remission from depression. The investigators compare individuals who have received placebo to individuals who have received 10 mg of escitalopram for one week. In this double-blind, randomized study the investigators a) compare the groups to observe the short-term effects of escitalopram and b) study the predictive value of these observations with respect to remission. Measures include, but are not restricted to, limbic emotional reactivity as assessed by fMRI, emotional processing, emotional memory, autobiographical memory.

Inclusion Criteria:

• Major depressive disorder with current major depressive episode according to a SCID-I/P interview
• Montgomery-Åsberg depression rating score 15-30
• Age 18-60

Exclusion Criteria:

• Borderline, schizoid or schizotypal personality, bipolar or any psychotic disorder
• Primary diagnosis is anxiety disorder: 300.00, .01, .02, .21, .22, .29, .23, .3, 309.81, 308.3, 293.89
• Significant current suicidal ideation, or history of a suicide attempt
• Lifetime substance dependence; Last-year substance abuse; Last month over 24/16 standard doses of alcohol/week; Lifetime use of illicit substances > x5; Any illicit substance use in last month
• Depressive disorder due to medical condition or chemical substance
• Antidepressant medication use in last 4 months
• Severe, unstable somatic illness
• Use of antipsychotics, mood stabilizers, systemic corticosteroids, β-blockers or daytime benzodiazepines (a small dose of ≤10mg zolpidem once daily is permissible)