The placebo/nocebo effect appears to be simply an example of the confirmation bias, a couple of other psychological biases and various other known statistical e

The placebo/nocebo effect appears to be simply an example of the confirmation bias, a couple of other psychological biases and various other known statistical effects. > False impressions of placebo effects can be produced in various ways. Spontaneous improvement, fluctuation of symptoms, regression to the mean, additional treatment, conditional switching of placebo treatment, scaling bias, irrelevant response variables, answers of politeness, experimental subordination, conditioned answers, neurotic or psychotic misjudgment, psychosomatic phenomena, misquotation, etc. These factors are still prevalent in modern placebo literature. The placebo topic seems to invite sloppy methodological thinking. Therefore awareness of Beecher's mistakes and misinterpretations is essential for an appropriate interpretation of current placebo literature. Beecher retrospectively attributed the improvements in the placebo groups to effects of the placebo administration. However, on the basis of the published data, in all of these trials the reported outcome in the placebo groups can be fully, plausibly, and easily explained withoutpresuming any therapeutic placebo effect. The published data of these trials make it quite obvious that there were a variety of reasons for the reported results, such as spontaneous improvements, additional treatments, methodological artifacts, etc. In some of the original trial publications even the authors themselves had explicitly written that there were no placebo effects. Source: The powerful placebo effect: fact or fiction?, GS Kienle, H Kiene, Journal of clinical epidemiology, 1997 (http://ukpmc.ac.uk/abstract/MED/9449934/reload=0;jsessionid=X21nexJpR1ki4fO6WJNg.0 http://ukpmc.ac.uk/abstract/MED/9449934/reload=0;jsessionid=...) Placebo interventions were again not found to have important clinical effects in general but may influence patient-reported outcomes in some situations Source: http://en.wikipedia.org/wiki/Placebo#Clinical_utility http://en.wikipedia.org/wiki/Placebo#Clinical_utility The effect, apparently, doesn't exist.