No clear boundary between placebo and effective treatment

In a recent editorial, Justman ¹ discussed the use of placebos in clinical practice. Of all the GPs who used pure placebos, fewer than one in ten reported that they explained to the patient that they were prescribing a placebo, according to a study by Howick et al. ² According to the same study GPs also disapproved of deception. Justman ¹ suggested that GPs might well be inconsistent by disapproving of deception and not telling patients that they are prescribed a placebo.

Howick et al. ² made a difference between pure placebos (such as sugar-coated pills) and impure placebos (such as peppermint pills). However, there is no sharp dividing line between pure placebo, impure placebo and active treatment. The word ‘placebo response’ is a misnomer, because a therapeutic response to an effective treatment can consist of a placebo component. ³ Research into depression suggests that patients sometimes respond to pure placebos and this correlates with changes in brain physiology. ⁴ One can wonder whether one of the examples of impure placebos from Howick’s study, ² peppermint pills, really has no genuine therapeutic effects for pharyngitis, although it is probably the sucking on the pills and not the peppermint. Because there is no sharp dividing line between placebo and active treatment, it is more useful to think about placebo as a form of treatment, which can be effective for some conditions such as depression and not for others such as cancer.

Practising doctors face a dilemma. They have to install hope, that the treatment will work and at the same time they have to give accurate information ⁵ about advantages and disadvantages of the proposed treatment. Mentioning the word placebo can be counterproductive, and it is not necessarily deception, if the word placebo is not used, given that even pure placebos can correlate with changes in the brain.