Placebo Mechanisms of Manual Therapy: A Wolf in Sheep's Clothing

Bialosky JE, Bishop MD, Penza, CW. Placebo Mechanisms of Manual Therapy: A Sheep in Wolf Clothing. JOSPT 2017

  • When a patient with pain experiences a positive outcome from manual therapy, we cannot answer with certainty as to why that occurs. 

  • The authors contest that placebo mechanisms deserve consideration as an important component of the treatment effect

  • Traditionally, "placebo" has had a negative connotation, implying an inert intervention without any treatment effect. However, the placebo response has been shown to be an active neurophysiological process associated with consistent responses in the spinal cord and supraspinal regions.

  • Placebo effects result in part from the psychosocial context surrounding the clinical encounter

  • Contrary to the nonspecific implication of placebo effects, the authors argue that placebo effects are highly specific and depending on the individual intervention. Placebo analgesia varies w/in individuals and analgesia to one form of placebo does not predict analgesia to another form of placebo.

  • The authors suggest that RCTs underestimate both the placebo and treatment effect sizes due to differences in participant preferences and expectations from those observed in regular clinical care

  • Manual therapists, having spent lots of time and often significant money honing their craft, may be troubled by the prospect of placebo mechanism playing a large role in treatment outcome, it may be comforting to acknowledge that rather than previously thought of inert mechanisms, the placebo effects are active neurophysiological effects generated by both pt and practitioner expectations as well as the experience of receiving skilled hands-on treatment from a highly-trained professional

  • Overall, the authors maintain, manual therapists should continue to pursue clinical excellence, while understanding that the time they have spent perfecting certain techniques may result in a better outcome may not be due to the proposed effect of the technique itself, but from improved contextual factors related to confidence, reputation, and therapeutic alliance.