Placebo effects in osteopathy and other manual therapies – What they are and why they matter to clinical practice, education, and research

Placebo effects are measurable changes in health outcomes arising from treatment context, driven by learning and expectancy mechanisms. While increasingly well documented and understood, their role in osteopathic and other manual therapies remains underexplored. Given the inherently complex and interpersonal nature of these interventions, understanding placebo and nocebo effects is essential for refining clinical practice, education, and research.

This narrative review synthesises current research on placebo mechanisms and their implications for osteopathic practice, education, and research. A non-systematic literature search was conducted using Google Scholar, structured by pre-defined learning outcomes, and prioritising high-quality studies and systematic reviews where available. Contradictory findings were sought and critically appraised to provide a balanced perspective.

Beginning with a historical overview and up-to-date summary of placebo-related concepts and mechanisms, the review highlights how expectancy, contextual factors, and psychobiological processes contribute to treatment effects in manual therapy. On this basis, the article advocates for a person-centred, biopsychosocial approach that leverages positive expectations while minimising nocebo effects. It also underscores the need for education models that incorporate placebo science to enhance clinical practice. Future research should prioritise well-designed efficacy trials, while also advancing knowledge of how expectancy and learning mechanisms influence treatment outcomes in manual therapies.