The role of personality factors and suggestion in placebo effect during mental stress test

Abstract

The aims of this study were first of all to document a placebo effect on systolic blood pressure and heart rate during mental arithmetic induced stress and secondly to assess the role of suggestion in producing this effect. Two types of placebo were used, a simple placebo and a placebo with an implied therapeutic action. Both were compared with alprazolam. A placebo response was seen in just over half of the volunteers when the cardiovascular changes to mental arithmetic induced stress in healthy volunteers were measured. This response appeared to be unaffected by the suggested therapeutic effect. Dominant, independent subjects, identified using the Cattell 16 PF personality test were less likely to respond to placebo. Alprazolam (0.5 mg) did not prevent, to a significantly greater degree than placebo, the systolic blood pressure or heart rate increases provoked by the mental stress.