The placebo effect has puzzled scientists for centuries. Philosopher Dien Ho argues that we now know how it works, and that this should transform our understanding of the relationship between mind and body. We must stop thinking of improvements in health due to placebo as somehow less real than those due to other medicines: there can no longer be a clean distinction between ill-health that’s “all in the head” and ill-health that involves a malfunctioning body. Ho argues that our improved understanding of placebos means that doctors should now harness their power in treatment, especially since research shows that they can be effective even when patients are told that they’re taking a placebo.

1. The therapeutic power of placebos

When healthcare researchers test potential new treatments, they use randomized clinical trials. Since the 1950s, placebos have been crucial parts of these trials. The placebo is made to resemble the treatment being tested, but lacks the experimental ingredients. For the treatment to be deemed efficacious, it must outperform the placebo, which is given to a control group. Otherwise, the treatment’s positive effects may be “mere” placebo effects. Advocates of evidence-based medicine consider double-blind randomized clinical trials with placebo controls as evidence of the highest quality.

___

It is possible to generate placebo effects even if subjects know that they are receiving placebos.

___