STUDY OF PLACEBO EFFECT WITH A PLACEBO TEST

This paper briefly reviewed several methodological problems in studies of the placebo effect. The importance of finding appropriate measures of placebo effect was emphasized. This led to an attempt to develop a more valid and reliable test of placebo reactivity. Use of the placebo test led to the following tentative conclusions:. Inferences made about placebo effects vary with the method of scoring placebo reactions. The placebo effect consists of a group of nonreactors to the placebo, and a second group of reactors but without regard to positive or negative direction. The reactive group is subdivided into predominantly positive or negative groups. Thus, comparing positive reactors with a combined group of nonreactors and negative reactors obscures important differences among groups. Patients with positive reactions to placebo tend to improve more rapidly and have a better prognosis than patients with neutral and negative reactions. Patients with absent and negative responses may respond to treatment eveually but not as predictably as positive reactors. Other confirmed predictions were that positive and negative placebo reactions would be unrelated to older age, lower intelligence, authoritarianism, duration and severity of illness, and diagnosis, and that placebo reaction would be related to anxiety and depression. The placebo test may combine the best features of a simple, standardized, quantitative, and reliable laboratory test of suggestibility with the clinical relevance and validity of the placebo effect. These conclusions are qualified by the limitations of the study, particularly the small sample. This paper should be considered a report of preliminary findings which should be investigated further. © 1968.