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Overcoming disagreement: a roadmap for placebo studies

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Abstract

In the field of placebo studies residual disagreement about the terminology ‘placebo’ and ‘placebo effect’ still persists. We differentiate between the conceptualization of placebos in clinical trials; and placebo effects understood as a psychobiological phenomenon. With respect to the latter, we argue that a scientific ‘placebo paradigm’ has emerged, indicating that—at least among placebo scientists—there exists relatively stable consensus about how to conceive of placebo effects. We claim that existence of a placebo paradigm does not protect concepts from revision; nonetheless, we argue that scientific progress is dependent on, and guided by relative conceptual stability. Therefore, to mount persuasive arguments for conceptual revision in respect of ‘placebo effects’ we argue, critics either need to defend the claim that a placebo paradigm is not underway, or that there are major scientific failings in respect of it. With these considerations in mind we examine three alternative proposals for conceptual reform: Grünbaum/Howick’s relativity models of placebo concepts; Moerman/Brody’s meaning response; and Nunn/Turner’s proposal for conceptual eliminativism. We derive two conclusions from this evaluation. First, we conclude that no convincing arguments have so far been presented for conceptual overhaul of ‘placebo effects.’ Notwithstanding this analysis, we conclude that refinement of this concept is likely. Second, we agree with Turner and Nunn that the term ‘placebo’ in the context of randomized controlled trials remains a source of confusion for many researchers, risking the design and scientific integrity of clinical findings. Therefore, in these contexts, replacing the term ‘placebo’ with ‘control’ is justified.

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Notes

  1. While we recognize that the conceptual debate occasionally extends to ‘nocebo’ and ‘nocebo effects’ discussion is mostly centered on placebo concepts. Therefore, in this paper we restrict ourselves to placebo concepts.

  2. Turner further asserts that it is an empirical question whether purging the old terminology will lead to improved methodological precision in clinical research; noticeably, however, the strength of his argument is premised on the speculation that terminological overhaul will indeed lead to such benefits (Turner 2012, p. 431).

  3. To this extent Kuhn’s proposals embody a version of naturalized epistemology.

  4. Even to adopt the broader notion that clinical trials/RCTs (somehow) comprise a paradigm arguably stretches conceptualization of the term beyond a Kuhnian interpretation. To put things another way: while we can acknowledge that the medical sciences are paradigm-led, the question about whether aspects of medical epistemology constitute a paradigm per se—similar to whether scientific epistemology (such as Kuhn’s insights) itself comprise a paradigm—is a meta-philosophical issue which takes us far beyond the remit of this paper (see Haack 2009 on characterizations of naturalized epistemology which speak to this debate).

  5. For descriptions of conditions under which open-label placebos are prescribed, including disclosure statements, see (for example): Kaptchuk et al. (2010), Carvalho et al. (2016) and Charlesworth et al. (2017).

  6. It should be pointed out, however, that in an unexpected and perhaps unnecessarily concessionary conclusion, Turner closes his 2012 paper by declaring that he would be “happy to use the term ‘placebo comparison’” (2012, p. 431).

  7. We note that, while conceptual refinement of ‘placebo effects’ is in the offing, fully developed testable hypotheses have not yet accompanied these developments.

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Acknowledgements

The authors thank the two anonymous reviewers and the Editor, Dr. Jay Odenbaugh, for helpful comments on a previous draft of this manuscript.

Funding

Charlotte Blease was supported by an Irish Research Council-Marie Skłodowksa Cure Award (CLNE/2017/226) and a Fulbright Award.

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Authors and Affiliations

  1. Program in Placebo Studies, General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA, 02215, USA

    Charlotte Blease

  2. School of Psychology, University College Dublin, Dublin, Ireland

    Charlotte Blease

  3. Consiglio Nazionale delle Ricerche (CNR), Rome, Italy

    Marco Annoni

  4. Istituto di Tecnologie Biomediche (ITB), Rome, Italy

    Marco Annoni

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  1. Charlotte Blease
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Correspondence to Charlotte Blease.

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Blease, C., Annoni, M. Overcoming disagreement: a roadmap for placebo studies. Biol Philos 34, 18 (2019). https://doi.org/10.1007/s10539-019-9671-5

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