Andrew Geers
Professor of Psychology, University of Toledo

A social psychological process approach for understanding placebo effects

An underlying goal of research on placebo effects is to develop a deeper understanding of the phenomenon so as to strategically incorporate it into patient care. Because placebo effects are strongly influenced by a patient’s subjective interpretation of the clinical encounter and the interpersonal context surrounding treatment, clarifying the various psychological processes at play should aid translation of research findings to clinical interventions that encourage placebo responses and discourage nocebo responses. In this talk, I will review and describe an empirically-supported multi-process model that can serve as a framework for research into the psychology of placebo effects. From this approach, the success or failure of treatment-relevant information in producing placebo effects depends to a large extend upon the specific communication variables at play, and most importantly, upon the processes by which those variables operate. This model leads to predictions regarding many facets of placebo effects, such as their directionality, durability, and likelihood to alter subsequent behaviors. The proposed conceptualization could help in synthesizing prior theoretical approaches regarding the occurrence of placebo effects and in addressing several unanswered questions in the placebo literature. The model also suggests steps that practitioners might take to amplify the placebo component of medical treatments and interventions. Research relevant to the model will be described and directions for future research will be highlighted.


Andrew L. Geers, Ph.D. is a Professor of Psychology at the University of Toledo (USA) and completed his degree at Ohio University. His research focuses on the advancement and application of social psychology theory within health and medical contexts. This research typically concerns (1) how beliefs/expectations shape the outcome of medical treatments and interventions (placebo/nocebo effects), (2) the causes and consequences of optimistic or pessimistic evaluations of future events, (3) the effects of involving individuals in their own health care decision making and (4) how to increase the initiation and maintenance of healthy behavior. He has published numerous empirical and conceptual review articles and his research has been funded by the National Institutes of Health.