To evaluate the effect of visit number, patient expectation, and rater expectation of the efficacy of escitalopram treatment in fixed doses of 10 and 20mg, based on baseline severity in patients with MDD.

This study is designed to determined if trial design, in the form of the frequency of patient contact (assessment visit numbers) has an effect on the efficacy outcome after 8-week treatment with escitalopram.

The placebo response is a major issue in clinical trials for psychiatric disorders-and especially in the management of depression. Possible contributing factors to this problem include diagnostic misclassification, issues concerning inclusion/exclusion criteria, outcome measures' lack of sensitivity to change, measurement errors, poor quality of data entry and verification, waxing and waning of the natural course of depression, regression toward the mean phenomenon, patient and clinician expectations about the trial, study design issues, non-specific therapeutic effects, and high attrition.

Over the past few decades, researchers have attempted to reduce the placebo effect in a variety of ways. Unfortunately, approaches with very little or no benefit have included restricting enrollment to selected populations, rater training, requirement of same rater, and placebo lead-in phases. Some benefits, although often marginal, have been derived from standardizing diagnostic procedures, managing clinicians' overestimation of change, simplification of study visits and assessments, minimizing nonspecific, therapeutic effects, extending trial duration, reducing number of sites, increasing the sensitivity of outcome measures, and reducing the number of treatment arms.

Thus far, there has been no attempt to develop new study designs aimed at reducing the placebo effect.

We are proposing a novel study design, suitable for doubleblind, trials in mood disorders. This design is aimed at characterizing and identifying both the overall placebo response rate and the sample size required for such

Inclusion Criteria:

1. Outpatients, men and women between 18 and 65 years of age (both extremes included)
2. DSM IV-TR criteria for a current MDE lasting between 3 and 12 months
3. Baseline MADRS total score > 22

Exclusion Criteria:

1. WHO-5 total score > 13 or a score > 3 on any single item of the WHO-5 (not revealed to the investigator)
2. Other primary or co-primary psychiatric disorder which is more distressful for the patient than MDDD, as evaluated by investigator
3. Patients with any history of mania/bipolar I disorder
4. Patients using medications which are contraindicated with the use of escitalopram
5. Known contraindication for the use of citalopram or escitalopram
6. Patients that have not responded to 2 or more treatments with an adequate dose of an antidepressant for an adequate time
7. Patients receiving formal behaviour therapy, or systematic psychotherapy
8. Unable to understand or read Hebrew and give written informed consent
9. Prominent suicidal ideation > 5 on item 10 (suicidal thoughts) of the MADRS]
10. Alcohol or substance dependence in the past 6 months