EFFECTS OF SUGGESTION AND CONDITIONING ON THE ACTION OF CHEMICAL AGENTS IN HUMAN SUBJECTS—THE PHARMACOLOGY OF PLACEBOS 12

Abstract

The effect of admn. of a drug or other chemical agent on a bit of muscle suspended in a standard soln. is predictable and reproducible because it depends only on the pharmacologic action of the agent admd. The effect of admn. of the same agent on an intact organism, however, is not necessarily predictable or reproducible because the pharmacologic action of the agent may either reinforce or run counter to other forces acting on the end organ at the same time. Despite this fact, drugs are often dealt with as if the intact organism were comparable to the water bath, and little interest has been manifest in factors other than their pharmacologic action which may determine or modify the effects of chemical agents in the human body. Measurable "drug effects" are described which are not attributable to the chemical properties of the agents administered. "Placebo effects" which modify the pharmacologic action of drugs or endow inert agents with potency are not imaginary, but may be associated with measurable changes at the end organs. These effects are at* times more potent than the pharmacologic action customarily attributed to the agent. Thus the familiar difficulty of evaluating in patients new therapeutic agents stems not only from inadequately curbed enthusiasm of the investigator, but also from the actual physiologic effects of their "placebo" action.