Demonstration to medical students of placebo responses and non-drug factors.

Abstract A class experiment for medical students Summary was devised to demonstrate the influence of the placebo effect and non-drug factors on response to drugs. The subjects were conditioned to expect sedative or stimulant effects, but all received placebo in one or two blue or pink capsules. Predictions about the size and nature of the placebo response and influence of the non-drug factors were made before the experiment and discussed afterwards. Four of six predictions were fully confirmed. Drug- associated changes were reported by 30% of the subjects and were severe in 1 or 2 individuals. Two capsules produced more noticeable changes than one, and blue capsules were associated with more sedative effects than pink capsules. Students rated the experiment highly both as a learning experience and for its relevance to their future practice of medicine.