Conditions: Depression
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 44
Healthy volunteers: no

Brief summary:
Major depression is a highly prevalent, frequently debilitating illness that too often fails to respond to currently available treatments such as antidepressant medication. Furthermore, randomized controlled trials of antidepressants consistently demonstrate large placebo effects. The investigators hypothesize that individual differences in the function of key brain circuits underlie the observed variability in clinical responses to both placebo and antidepressant medication. This study will test this hypothesis by recruiting treatment-seeking volunteers with major depression, with or without comorbid nicotine dependence. Volunteers will participate in positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) scans in the context of a treatment trial in which they will receive both placebo and antidepressant medication. A major goal of the study is to improve prediction of individual clinical responses in future treatment trials in which brain imaging may be unavailable, and to study the mechanisms of antidepressant response in Major Depression.

Detailed description:
We performed a single-blinded two-week cross-over randomized controlled trial of two identical oral placebos (described as having either potentially "active" fast-acting antidepressant-like effects or to be "inactive") followed by a 10-week open-label treatment with a selective serotonin reuptake inhibitor (SSRI) or in some cases, another agent as clinically indicated. The volunteers were studied with PET and the µ-opioid receptor selective radiotracer \[11C\]carfentanil after each 1-week "inactive" and "active" oral placebo treatment. In addition, 1 mL of isotonic saline was administered intravenously (i.v.) within sight of the volunteer during PET scanning every 4 min over 20 min only after the 1-week active placebo treatment, with instructions that the compound may be associated with the activation of brain systems involved in mood improvement. This challenge stimulus was utilized to test the individual capacity to acutely activate endogenous opioid neurotransmission under expectations of antidepressant effect.

Arms:
arm 1: This arm gets a placebo that they know is a placebo (called inactive), then has 2 scans performed (FMRI and PET), then a 2-3 day washout, and then gets a so-called "active medication" (which is also actually a placebo), and another pair of scans. Following these, participants receive 10 weeks of open-label antidepressant administration (Celexa or alternative as explained in intervention description). First line antidepressant will be Celexa unless not clinically indicated. arm 2: This arm gets a placebo that they don't know is a placebo (called Active), then has 2 scans performed (FMRI and PET), then a 2-3 day washout, and then gets a so-called "inactive medication" (which participants know is a placebo), and another pair of scans. Following these, participants receive 10 weeks of open-label antidepressant administration (Celexa as explained in intervention description). First line antidepressant will be Celexa unless not clinically indicated.

Interventions: intervention 1: Placebo, identified as placebo to participants intervention 2: Celexa or other antidepressant as clinically indicated intervention 3: Placebo, identifed to participants as "Active medication"
Intervention descriptions: intervention 1: White tablets intervention 2: Open label s-citalopram, 20 mg start up dose, increasing to 40 mg as clinically indicated; If prior non-response to this medication is noted by the patient, alternative treatments may include another first-line antidepressant:fluoxetine 20 mg; paroxetine up to 60 mg; sertraline up to 200 mg; bupropion up to 300 mg intervention 3: Blue Capsule

Protocol document: