Useful links about placebos

 

Short analysis of the paper:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0058247

Basically: their definition of placebo is quite amazingly different from what is used elsewhere. Placebos are commonly thought of as a sugar pill or chalk tablet – a biologically inert substance which cannot directly treat the disorder it is offered for.

This paper decided that these were ‘pure placebos’ and that lots of other things were ‘impure placebos’, such as

“Positive suggestions

  • Nutritional supplements for conditions unlikely to benefit from this therapy (such as vitamin C for cancer)
  • Probiotics for diarrhea
  • Peppermint pills for pharyngitis
  • Antibiotics for suspected viral infections [5]
  • Sub-clinical doses of otherwise effective therapies [32]
  • Off-label uses of potentially effective therapies
  • Complementary and Alternative medicine (CAM) whose effectiveness is not evidence-based [33][34]
  • Conventional medicine whose effectiveness is not evidence-based [35][36][37][38]
  • Diagnostic practices based on the patient’s request or to calm the patient such as
    • Non-essential physical examinations
    • Non-essential technical examinations of the patient (blood tests, X-rays)”

They are wrong; homeopathy or vitamin C for cancer ( their ‘non evidence based’ complementary medicine) is pure placebo, and it involves deception as well.

Whereas, clinical examination when someone has say mild symptoms of a cold does not involve deception. It may also not be very necessary either, but if it is done with discretion in order to reassure a patient that they were correct about the origin of their illness, and that they do not have, say,  a chest infection, and is not promised to do anything else, is not a ‘placebo’. It may be unnecessary; many things in medicine may be.  Whereas, someone who sets up a private health screening clinic and offers ‘whole body check ups’ which will somehow promise better health, this is deception, because the promise is not  based in evidence.

Similarly, positive suggestion is evidence based in some circumstances, for example, if a group of patients are given exercise to do for health, only the group told that it will help with self esteem will report this benefit.

The literature on antibiotics for viral infections, is in a post from Inside Health below – this is a whole other ball park. The question is not about antibiotics in viral infections, it is about the role of antibiotics in upper respiratory infections full stop – they don’t really work, basically. This isn’t about GPs prescribing antibiotics, but about an antibiotic prescribing culture.

This paper does not show that placebos are being given out in quantity by GPs. It may show that GPs who prescribe homoeopathy accept that it is a placebo. Other than that, I can ‘t quite understand how it’s attracted so much attention.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0015591

http://www.hta.ac.uk/execsumm/summ1019.htm

 

Chapter 16  The unseen benefits of professional healthcare

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2 Responses to “Useful links about placebos”

  1. Keith Walker March 21, 2013 at 1:30 pm #

    Thanks Margaret. I don’t know why it got such attention, but the way it was reported suggested that some GPs had ‘admitted’ (ie guilty of) using placebos, which to non-medics like me means giving out sugar and chalk pills when they ought not to. Some of my colleagues interpreted that as outrageous, since they paid prescription charges for nothing, and presumed it was done to get them out of the surgery more quickly. Perhaps this is the angle that the media hoped would attract public attention. Using ‘admitted’ is powerful in that regard.

  2. David Colquhoun March 22, 2013 at 12:01 pm #

    This post is, as usual, a superb analysis.

    The only thing that I’d like to add is to draw attention to Hróbjartsson & Gøtzsche
    http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003974.pub3/full

    This, and other evidence, seems to be showing that the placebo effect, though certainly real, is often too small and too transient to have much clinical significance. In other words, when people who get better after an ineffective treatment, it’s quite likely that they’d have got better anyway. Insofar as that’s true, in removes the last plank for alternative scamsters. It’s interesting that some of them seem now to admit that their treatments are only placebos, but still seek to justify them because of the great power of placebo effects. That seems to be untrue.

    Of course if all you mean by placebo is giving the patient a physical examination that isn’t (as far as you can guess) strictly necessary, in order to reassure them, that’s totally justified in my opinion.

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