The placebo response : a study of the personality correlates of placebo reactors

Abstract

A definition of placebo accepted in this study was that of "an inactive substance or preparation,. formerly given to please or gratify a patient, now used in controlled studies to determine the efficacy of medicinal substances." The placebo effect was accepted as any effect attributable to a pill, potion or procedure, but not to its pharmacodynamic or specific properties. The placebo was distinguished from the placebo effect, the placebo being the agent which might or might not result in the effect. Many questions about the placebo have become pressing. P.ow does it work? On whom does it work? When does it work? While the use of the placebo is not new, the wide variability of its effects and the factors influencing this variability, have remained relatively unexplored areas. Most reports in the literature have consisted merely of the citing of such an effect, with little or no additional information being offered to account for the ·Underlying psychological and physiological variables involved. The opportunities opened by the placebo are unique, for it cannot possibly enter into any process by virtue of its· chemical composition. The following are some reasons why research in this area appears vitally necessary. (1) Placebo reactors may change the slope of the dosage - to - response curve, and in consequence the sensitivity of the experiment. (2) An effective durg may be wrongly discarded because data has been diluted by inclusion within the test group, a large number of placebo reactors. (3) The optimal dosage of a standard drug may be underestimated if the placebo reactor group within the population is large and readily relieved. The aims of the present study were to find if any consistent type of placebo reaction was elicited from a group of experimental subjects, and to attempt to study the relationship between particular personality variables and the tendency to react to the administration of placebo. A questionnaire was developed to measure these reactions. It was given to forty-five female subjects for four days, and then for another four days while these subjects received placebo, administered as. an unnamed drug on which an experimental survey was being carried out. In addition, a control group of matched subjects filled in the questionnaire for eight days. The M.P.I., and T.M.A.s. were used as definitions of the personality traits of anxiety, extraversion and neuroticism. A placebo reaction score was developed. This was the total frequency of response change shown by any one subject, when her pre-placebo responses were compared to her responses while receiving placebo. Show more