PSYCHOLOGICAL MECHANISMS OF NEGATIVE PLACEBO ACTION. AN EMPIRICAL ANALYSIS

The aim of the paper is an attempt to research psychological mechanisms of the placebo action (expectancy, classical conditioning and anxiety) and their relationships.The effect of negative placebo as one of the potential effects of the action of placebo administered in the guise of an adverse method or as its component is distinguished. An experiment on psychological mechanisms of negative placebo action (namely hyperalgesic) is presented. The results of the experiment show that expectations are sufficient to induce the effect of negative placebo but conditioning is not sufficient to induce this effect and have no impact on the strength of the effect induced by expectations. A significant relationship between expectations and pain anxiety was determined. It was also demonstrated that it was possible to induce the effect of negative placebo despite the lack of intentionally evoked expectations. The results support expectancy and anxiety but doesn't exclude classical conditioning as the mechanisms of negative placebo action.