Date : Since 09/06/2017
Place : Read article!Bioreagents
Open-Label Placebos: "I knew they were sugar pills but I felt fantastic"
May 2017: A review of five studies, involving 260 patients found that placebos are effective even when patients know they don't contain any medicine.
Take a look at this article of The Guardian about how open-label placebos can improve pain perception.