Patient Expectancy as a Mediator of Placebo Effects in Antidepressant Clinical Trials

Objective: Causes of placebo effects in antidepressant trials have been inferred from observational studies and meta-analyses, but their mechanisms have not been directly established. The goal of this study was to examine in a prospective, randomized controlled trial whether patient expectancy mediates placebo effects in antidepressant studies. Method: Adult outpatients with major depressive disorder were randomly assigned to open or...