One of the main problems in the present age is the enormous amount of information we have access to in every instant involving all types of questions, without having any direct experience on the topic. Therefore, in order to make appropriate choices it is important to discriminate between fake or scientifically proven news. This problem also applies to some of the most used words in medicine: placebo and placebo effect, which are not always fully understood by health professionals. In the past years a modern interpretation of placebo and its effects has become evident. This new interpretation is also important in order to make progress in the study of placebo. This mini-review will address the meaning and the use of the placebo effect in medical practice, and will deal with the biochemical mechanisms underlying the phenomenon mainly in the field of analgesia and pain perception. In fact, the placebo and nocebo effects, even when seen as psychological or ritual aspects of the therapeutic act, may change the biochemistry and the neuronal circuitry of the brain. Moreover, the mechanisms activated by placebos and nocebo have been found to be similar and often the same as those activated by drugs, whereas research has identified many types of responses emerging from different types of placebo. Finally, ethical problems arising from the use of placebo in medicine will be mentioned.
Keywords: Placebo, nocebo, fake news, myths, scientific evidence