1. Sign our petition calling on Cochrane to withdraw their review of Exercise Therapy for CFS here.
    Dismiss Notice
  2. Guest, the 'News in Brief' for the week beginning 18th March 2024 is here.
    Dismiss Notice
  3. Welcome! To read the Core Purpose and Values of our forum, click here.
    Dismiss Notice

Science based Medicine: Placebo Myths Debunked

Discussion in 'Research methodology news and research' started by Cheshire, Nov 15, 2017.

Tags:
  1. Cheshire

    Cheshire Moderator Staff Member

    Messages:
    4,675

    https://sciencebasedmedicine.org/placebo-myths-debunked/
     
    Dolphin, Inara, Woolie and 12 others like this.
  2. Hoopoe

    Hoopoe Senior Member (Voting Rights)

    Messages:
    5,234
    The main thing to know is that the idea of the powerful placebo was based on an article published in 1955 which jumped to a conclusion involving the healing power of suggestion instead of carefully considering other explanations for why patients often improved even with a sham treatment.

    Some reasons an illness can improve or falsely appear to improve even without effective treatment:

    - Many illness get better without treatment.
    - A change in how patients perceive, think or report their symptoms, such as answers of politeness, hope, undergoing therapy that aims to change perception of the illness, etc.
    - Patients are receiving some other treatment at the same time.
    - Fluctuations in illness severity, occurring by chance at a time that creates the appearance of a sham treatment working.

    There seems to be a great deal of confirmation bias in the literature promoting the idea of the powerful placebo.
     
    Last edited: Nov 15, 2017
    Dolphin, Inara, Woolie and 10 others like this.
  3. Obermann

    Obermann Senior Member (Voting Rights)

    Messages:
    123
    Location:
    Stockholm
    It is interesting to note that there has been a study where ME/CFS patients were treated with homeopathy. It is difficult to compare the results directly with the PACE study, as Weatherley-Jones et al used the multidimensional fatigue inventory (MFI) for outcomes. However, if the improvement is normalized by its standard deviation (SD), the fatigue for patients that underwent homeopathy improved by 0.7, the fatigue in the CBT group in PACE improved by 1.0, and the fatigue in the GET group in PACE improved by 1.2.* Note that the homeopathy study was blinded, and that the placebo response probably would have been even larger in a non-blinded trial.

    This comparison suggests that the order of magnitude of the subjective improvements in PACE is consistent with a placebo response. If Peter White and colleagues believe that subjective outcomes are appropriate because “that is how the illness is defined”, then they should also promote homeopathy as a useful treatment.

    Weatherley-Jones E, Nicholl JP, Thomas KJ, et al. A randomised, controlled, triple-blind trial of the efficacy of homeopathic treatment for chronic fatigue syndrome. J Psychosom Res. 2004;56(2):189–97.

    * As the SD of the outcomes were specified at baseline and end of treatment in PACE, I derived the SD for the difference under the assumption that the baseline values and the improvements were independent.
     
    Last edited: Nov 16, 2017
    Inara, Woolie, Valentijn and 2 others like this.
  4. Barry

    Barry Senior Member (Voting Rights)

    Messages:
    8,385
    Can we include this article in our science library please @Cheshire, because I find it very educational.
     
    Inara, Woolie, Valentijn and 3 others like this.
  5. Barry

    Barry Senior Member (Voting Rights)

    Messages:
    8,385
    How familiar is that! The BPS crew's reaction to their unwarranted reliance on subjective outcome measures, is to downplay the importance of objectivity, and instead start getting creative why subjective outcomes are adequate.
     
    Inara, Valentijn, Esther12 and 2 others like this.
  6. Esther12

    Esther12 Senior Member (Voting Rights)

    Messages:
    4,393
    I'm sure they've posted a nearly identical article before!

    Still, it seems that it needs repeating.
     
    Inara, Woolie, Barry and 1 other person like this.
  7. Valentijn

    Valentijn Guest

    Messages:
    2,275
    Location:
    Netherlands
    Damn, I guess this means that we can't take the word of royal German veterinarians as proof that homeopathy works :rolleyes::
    I don't completely agree with this regarding the size of the placebo effect. If it's deliberately exploited as part of the treatment process, it makes sense that the placebo effect will be bigger, such as with deliberate brain-washing regarding symptom denial:
     
    Dolphin, Inara, Woolie and 6 others like this.
  8. Woolie

    Woolie Senior Member

    Messages:
    2,918
    done. see https://www.s4me.info/index.php?thr...l-of-that-shiny-new-study-a-bibliography.212/ I've included the following summary:
    Yay, first time we've cross-referenced an article in the library with its corresponding S4ME discussion!

    Note in that section of the library, there are loads of articles on the placebo effect, expectation effects and other artefacts that affect clinical trials. There are also some that assess how big these effects might be.
     
    Dolphin, Inara, Barry and 5 others like this.
  9. Woolie

    Woolie Senior Member

    Messages:
    2,918
    The Lilienfeld article in the science library talks more comprehensively about spurious factors affecting psychotherapy trials in particular:

    https://www.s4me.info/index.php?thr...l-of-that-shiny-new-study-a-bibliography.212/

    Lilienfeld et al refer to this effect as "Response shift bias". (you're taught to evaluate your symptoms differently, and this has a direct effect on self reported symptoms, in the absence of genuine change).
     
    Snow Leopard, Dolphin, Inara and 7 others like this.
  10. Barry

    Barry Senior Member (Voting Rights)

    Messages:
    8,385
    So people would especially self report differently if they are convinced they have a real underlying illness, but are reprogrammed to then believe they are fundamentally out of condition, and can can exercise their way back to health again. Presumably there must be a timing issue here also, because the self reporting will be affected by whether the subject is on the crest of a euphoric wave of optimism following their reprogramming, or later after the bubble has burst and the truth dawns once more.
     
    Inara, Viola, Woolie and 3 others like this.
  11. Woolie

    Woolie Senior Member

    Messages:
    2,918
    Totally. Hence PACE's CBT and GET "worked" for a while, and then stopped working (no benefit at long-term follow-up).
     
  12. Adrian

    Adrian Administrator Staff Member

    Messages:
    6,479
    Location:
    UK
    That is basically PACE with CBT/GET as well as Smile. Crawley's trials are designed to use this effect to get a positive effect.

    I think there is also a timing issue in when forms are filled out. If you give people the chance to send forms back over a month or two they may wait till they are at their best point and report that.
     
  13. Wonko

    Wonko Senior Member (Voting Rights)

    Messages:
    6,674
    Location:
    UK
    So wouldn't it be much more ethical to simply inject people with morphine and then get them to fill in a questionnaire saying how they feel - and then produce a paper or 27 that says morphine relieves some symptoms and improves the sense of well being in those with chronic illness?

    Coz apart from the fact that it would be more reproducible, and "easier" on people's health, I can't see much of a difference - well and cost - it doesn't cost £5 million to supply a few hundred people for a few months.

    ....and whilst it is unlikely to improve anyones long term health, it's also unlikely to damage them either, the same cannot be said for GET/CBT.

    I'm not suggesting this as a "treatment", I'm simply using it as an example to point out the absurdity.

    Hopefully.
     
  14. NelliePledge

    NelliePledge Moderator Staff Member

    Messages:
    13,145
    Location:
    UK West Midlands
    Nice one @Woolie for flagging the term response shift bias

    Next time any of the BPS crowd do anything public we should hashtag them with it on social media
     
  15. Inara

    Inara Senior Member (Voting Rights)

    Messages:
    2,734
    Yeah, but let them BPS people have their share of the cake...it's quite unfair to give everything to pharma, isn't it? :D
     
    Luther Blissett and Woolie like this.
  16. Inara

    Inara Senior Member (Voting Rights)

    Messages:
    2,734
    I can absolutely agree with that, at least in my case. When I realized I'm actually doing that I fixed a certain date to fill out the forms. I also can agree to the fact that I wanted to please the clinician. I am very strict, though, and honest in that aspect, so I disciplined myself.

    Interesting topic, and thanks for the information!
     
    Luther Blissett, Woolie and Wonko like this.

Share This Page