We disagree with Dr Swann that a nocebo effect and a variation in event rates in the studies invalidate the results of our study.¹ Firstly, we disagree that a prominent apparent nocebo effect biases toward underdetection of side effects in placebo controlled trials. The nocebo phenomenon refers to symptoms, physiological changes, or both that follow administration of a placebo that the patients believe to be an active drug.² Since patients enrolled in placebo controlled trials are unaware of the medication they receive, the nocebo effect should be equally exerted in both treatment groups. In fact, the nocebo effect furnishes a justification for including placebos in clinical trials because it permits a more accurate appraisal of the side effect profile of the active medication. Without such a …