One of the rare studies into the action of the placebo effect in ‘non-blind’ clinical trials was undertaken by Lee C. Park and Uno Covi at the Johns Hopkins University School of Medicine in 1964. ‘Non-blind’ means that patients were informed that the pills they were issued were totally inert, that they were placebos, and in this case they were also assured that despite this the pills would be of benefit to them. The study concluded:’The primary finding is that patients can be willing to take placebo and can improve despite disclosure of the inert content of the pills; belief in pill as drug was not a requirement for improvement.’

(Some first-hand reports on our Testimonials page.)

Ref. L. C. Park, U. Covi, Nonblind Placebo Trial – An Exploration of Neurotic Patients’ Responses to Placebo When Its Inert Content Is Disclosed, Archives of General Psychiatry, April 1965, Vol. 12, pp. 336-345