In a 1962 experiment Drs. Harriet Linton and Robert Langs told test subjects they were going to participate in a study on the effects of LSD, but then gave them a placebo instead. Nonetheless, half an hour after taking the placebo, the subjects began to experience the classic symptoms of the actual drug, loss of control, supposed insight into the meaning of existence, and so on. These “placebo trips” lasted several hours.
