The Placebo Effect in Physical Therapy

Barr JO; Physical Therapy Department, St. Ambrose University, Davenport, IA.

PURPOSE: This presentation examines the placebo effect as an important psycho-physiological phenomenon that too often is not accounted for in PT research and practice. 

DESCRIPTION: Although the placebo effect has been discussed in the medical literature since the early 1950s, it has received scant attention in the PT literature.  In this era of increasing concern about the effectiveness of PT interventions, researchers and clinicians need to be able to distinguish among outcomes attributable to the natural history of resolution for a condition, placebo effects, and true treatment effects. Researchers need to recognize and control for factors that might enhance the placebo effect to a magnitude that exceeds that from a therapeutic intervention. In formulating a prognosis, PTs need to have knowledge of the magnitude and time course of the placebo effect.  Information about the incidence and psycho-physiological basis for the placebo effect will be presented.  Factors that predispose subjects / patients to experience a placebo effect (e.g., anxiety, expectation, belief in the intervention, etc.) will be examined. The magnitude and typical time course of the placebo effect will be discussed.  Strategies for either enhancing or minimizing the placebo effect in research and clinical settings will be suggested.  Finally, research studies that have inadequately controlled for the placebo effect will be critiqued.

SUMMARY:  Placebo effects need to be better accounted for in PT research and clinical care.  This presentation discusses the basis for and potential impact of the placebo effect in research and clinical applications.  Strategies that can be used to better control for the placebo effect are presented.  Examples of research that has inadequately controlled for placebo effects will be discussed.

IMPORTANCE:  In order to appropriately address the effectiveness of therapeutic interventions, PTs need to account for the placebo effect in both research and clinical settings.  This presentation provides information that will facilitate greater recognition of and control for potential placebo effects in physical therapy.

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