Neurobiological Bases of Placebo Response in Major Depressive Disorder

Inclusion Criteria:

- Meets diagnostic criteria for Major Depressive Disorder

- Written informed consent

- Men or women aged 18-60 years old

- A score of 18 or greater on the HAMD-28

- Patient must continue to meet criteria for current MDD at baseline. Patients must
have Clinical Global Impression Improvement (CGI) scores ≥ 3 (i.e. minimally improved
or less) from the screen to the baseline visit

- Agreeing to, and eligible for all procedures (only patients 18-45 will be eligible
for MR-PET study)

Exclusion Criteria:

- Pregnant women or women of child bearing potential not using a medically accepted
means of contraception

- Patients who are a serious suicide or homicide risk

- Unstable medical illness including cardiovascular, hepatic, renal, respiratory,
endocrine, neurological, or hematological disease, uncontrolled seizure disorder

- The following DSM-IV diagnoses: a) organic mental disorders b) substance use
disorders, including alcohol, active within the last year; c) schizophrenia; d)
delusional disorder; e) psychotic disorders not elsewhere classified; f) bipolar
disorder; g) acute bereavement; h) borderline or antisocial personality disorder i)
current primary diagnoses of panic disorder, social phobia, GAD, or OCD (disorders
that present as chief complaint and/or have their onset preceding the onset of MDD),
l) Patients with mood congruent or mood incongruent psychotic features

- Currently taking any of the following exclusionary medications: antipsychotics,
anticonvulsants, mood stabilizers, stimulants, antidepressants, potential
antidepressant augmenting agents (e.g., T3, SAMe, St. John's Wort, lithium,
buspirone, Omega 3 fatty acids). If it is determined that it is safe to discontinue a
medication, the patient will be required to wait a period equivalent to at least 5
half lives of the drug before the screening

- Patients who have taken an investigational psychotropic drug within the last year

- Patients who have not responded to one or more antidepressant trials of adequate
doses (e.g., fluoxetine 40 mg/day or higher) and duration (e.g., for six weeks or
more) over the past five years, as defined by the MGH-ATRQ

- History of inadequate response or poor tolerability to citalopram or escitalopram

- Any concomitant form of psychotherapy (depression-focused)

- Receiving or have received during the index episode Vagal nerve stimulation, ECT or
rTMS, or other somatic antidepressant treatments

- Any reason not listed, determined by the site PI or study clinician, constituting
good clinical practice and making participation in the study hazardous

- Contraindications to fMRI scanning and MR-PET scanning (including presence of a
cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips
in the head or previous neurosurgery, prosthetic heart valves, claustrophobia)

- MR-PET-specific exclusion criteria: Patients who are younger than 18 or older than 45
years of age