Discussion in 'Latest ME/CFS Research' started by Dolphin, Aug 25, 2016.
Free full text: http://simonwessely.com/Downloads/Publications/CFS/176.pdf
The comparison made between the placebo response in CFS and other conditions may not be like-for-like i.e. the threshold for being a responder might be different in other conditions.
This is the information we are given on the other conditions. I haven't looked into how a responder was defined or whether these are representative figures or not.
Is this why PDW wants to shut out the world from patients doing his treatments? He could do with a good placebo response.
Pooled Placebo Response
Low (N=8): 14.0%
Medium (N=5): 16.5%
High (N=16): 24.0%
I wonder how much of this could be explained by placebo type (behavioral, oral, or injected)
N of Studies With Data
Unit of Increase
1 category (out of 3)
Coefficient in %
95% CI in %
1.3 to 11.9
They do say:
The Coefficient in % for Intervention type was 5.0
I wouldn't be surprised if similar patterns are not found in other conditions (they don't mention this).
So the percentage of responders to placebo among CFS patients is 19.6%, in other conditions it's around 30%. The "recovery" rates reported in the PACE recovery paper (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3776285/) are APT: 8%, CBT: 21%, GET: 21%, SMC: 7%. Go figure!
The authors seem to believe in placebos having real effects
rather than the findings being artefacts of one sort or another e.g. spontaneous remission.
Buried in the paper are these important points. It would be interesting to know whether the authors had them in the initial draft or whether they were suggested by a reviewer
Notice how they use the word "controversial" suggesting the authors do not necessarily agree with the findings.
If studies in other conditions did not deal with missing data in this way, this could give an artificially low percentage of responders in CFS studies compared to other conditions.
They refer to "strict" and "loose". However it doesn't read necessarily mean that it would be harder to achieve a response with a strict criterion versus a loose criterion; see how they define them here:
Is relaxation therapy really a good placebo?
Also "standardised medical care" sounds more like it might involve no therapy. I wonder does it include "waiting-list controls" who, it has been said, sometimes report poor results due to dissatisfaction with not getting a therapy.
This is not that long. The longer the follow-up period, more chance there is for spontaneous improvement. I wonder how long the follow-up was in the non-CFS studies.
Saying that, follow-up duration length was not associated with placebo response in this study.
No objective outcome measures were used:
The final paragraph contains the most psychobabble it seems to me::
Technically speaking this study gives us no information about the specific expectations regarding CBT and GET. Placebo effects could be higher with them for various reasons perhaps e.g. claims made about efficacy, energy participants need to invest, reframing of symptoms, etc. and how this might lead to response biases.
I'm not convinced one should hype the efficacy of therapies in order to increase the "placebo response". I'm not sure that a "placebo response" has much effect on objective measures. Getting more people to say they feel a bit better without necessarily being any better does not seem to me to be a worthy aim in most contexts.
I think that might render the whole analysis invalid: you generally need a lot more observations than paramaters to avoid violating assumptions needed to apply the tecnique. Any experts here?
Whatever explanation is favored, the clinical implication is the need to provide existing evidence supportive of CBT and GET in a language accessible to patients, and if antidepressants are to be used, to make it clear that this is a treatment for depression rather than CFS itself.
...I read this as "we must convince patients that theres a benefit and use lanaguage to do this" - perhaps the bias of this paper is the authors seeking to find a lower placebo expectancy so they can say in future "placebo is lower in CBT for CFS than in other conditions " (but on a limited number of studies with no real blinding - we cant sorry)
This paper struggles to convince me on many levels. 1. the studies reviewed have such different outcomes and approaches, making cross comparison difficult 2. Many of the studies didnt really try to capture expectancy so hard to do a post-hoc analysis of expectancy. 3. I dont understand the search limits of 2000-2002, 4. there is a lot of design bias in this study - the authors basically draw up their own parameters of assessment to pool data, 5. I think some distinction needs to be made between pre-CBT expectancy and post-CBT expectancy ie CFS patients may have low expectancy going in, but may have higher expectancy after spending time with the therapy and we need to extend the term out from just expectancy of benefit to "return on investment of time and effort" ie the patients who stick with CBT may feel they have invested in it, thus there must be a benefit, that goes beyond simple expectancy 5. No blinding, no real controls, sorry, weak here.
*in drug trials of placebo, the sugar pill is comapred against the drug - two white pills given in the same way - why do the authors not ask for research on sham CBT given in the same way as real CBT to do the same as drug trials? - thats the big question, why is CBT protected from placebo research
You can also try a Google Site Search
Separate names with a comma.