This is a continuation of a very old post I did on the placebo effect. To summarise, a lot of people seem to think the placebo effect is somehow related to “mind over matter” and the body healing itself because it expects to be healed. In reality, the placebo effect is when an improvement is reported for any reason other than the physiological effects of a treatment. This does not automatically preclude any self-healing mechanisms but it means that the cause can be a lot more prosaic.
What I didn’t mention was the idea that there is no placebo effect. Or at least that it’s not an effect at all since the more objective your measure of patient condition the more the effect disappears (when compared to doing nothing at all). From the always excellent Science Based Medicine blog, I recommend this recent post by David Gorski which argues for this view using a recent trial on asthma.
I won’t make this wordy, the graphs from the study say more than words can. I present the two graphs in reverse order for effect. The study compared four interventions for asthma in people who have moderately severe asthma. This is a much more interesting setup for the study of the placebo effect than just treatment/placebo. The treatments were Albuterol (an asthma drug on the market, also commonly known as Ventolin), a placebo inhaler, the placebo treatment of sham acupuncture using a retractable needle. Below are the subjective results: what kinds of improvements did the patients feel?
Once that’s sunk in, behold the objective results: what measured lung capacity improvements were there?
Yes it’s true that even the “no treatment” group may have been experiencing an effect simply by participating in the study. Even so, this illustrates what is meant by the idea that placebo is not an actual effect. Or rather, there is an effect but it’s so small so as to be lost in the much greater effect(!) of doing nothing. And it does provide support against the idea that it’s an effect that can be harnessed, or that it’s ok to give placebos as part of a treatment program. At least for conditions with objective measures.
Unsurprisingly, the pro-placebo conclusion given in the study is to say black is white. To quote Gorski (emphasis mine), “the spin on this study is not that placeboes don’t result in objectively measurable improvements, which is the correct conclusion. Rather, the spin is that subjective symptoms are as important or more important than objective measures; so let’s use placeboes.”
Of course this is just one study and it may have some other flaws, although the protocol seems pretty basic and unequivocal. But the above reaction looks like an example of a well-established — and very sad — result in psychology. When people are presented with science that contradicts their belief, the most common response is to start believing science itself is bunk. If you’re feeling too optimistic today, this article by Chris Mooney on the science of why we don’t believe in science will fix that.
[EDIT]: After I wrote this up, Steve Novella did a post on Neurologica that I recommend, which discusses the same study — and presents the same 2 graphs in the same order.
10 comments ↓
[...] is shown to work as well as a placebo, and I’ll show you research that shows that a placebo is no better than doing nothing at all. Invariably, whenever acupuncture comes up in conversation, it turns to our favorite phrase, [...]
The mention of asthma as a purportedly scientifically understood and treated disease shows the reliance on a how many angels on the head of a pin type of argument here, betraying the aims of the authors to confirm the medical wisdom on the disease. The extensive scientific writings on inspiratory muscle training and the widespread use of the respective appliances clearly indicates not only that asthma symptoms may be eliminated by such training but also that the muscle detraining effects of asthma drugs must be responsible for the epidemic. Furthermore all too relevant is the utter absence of any serious enquiry about causation due to treatment even despite the alarming increase in asthma morbidity. Obviously anyone afflicted by the disorder should consult a physician aware of the developments. RF
I’m not sure what this has to do with the post. Even if what you say is true (which goes against everything I know about this so some major citations would be needed), the only thing needed for my point was that administering Albuterol increases the FEV by 20% in the cases measured. Do you dispute this?
(Albuterol could also give you twelve autisms and seventeen carcinomas the day after the study but this would not change the point about the placebo effect being largely due to the patient’s [often false] perception of their condition.)
The standard concept/treatment of asthma with bronchodilators leads to more asthma .(http://www.moh.govt.nz/notebook/nbbooks.nsf/0/f96719201ea758294c2565d700187e74/$FILE/asthma.pdf especially page 7). Attempts to nobitate asthma by mentioning it in certain other contexts should be challenged. and a doctor’s advice on inspiratory muscle training sought. RF
Very interesting — not only does your response not address the main point of my previous comment but the citation provided does not appear to support your [tangential!] point at all! There is no evidence presented that the increase in asthma is due to bronchodilators, in fact it discusses exactly the type of causes that are consistent with the rise being attributed solely to environmental causes.
Either way, your claims about the long term harm of asthma drugs are in no way relevant to the study above. Again, unless you are claiming that Albuterol does not increase FEV to the levels given in the graph when administered.
To be brief: Albuterol is purely symptomatic, IMHO inspiratory muscle training depends substantially on the muller (or mueller) effect which opens up collapsed airways: Statistics/epidemiology (circumstantial evidence) should outweigh the clinical stuff here.
Why discount the IMT hypothesis that asthma is so much influenced by training the muscles? Unloading them would weaken the same. RF
I’m stunned — once again your latest comment, even if 100% true, does not address any of my previous comment. I think we’re going in circles here.
See http://chronicle.com/blogs/tweed/dead-fish-lights-up-when-shown-pictures-of-humans/8130. Who is to say that asthma spcialists are any less gullible than many a neuroimager. An ivory tower or ship of fools may be inevitable so we are forced to be in this “good company” RF
well, this study shows that there is no “placebo effect” for healing asthma (or more precisely increasing FEV).
It doesn’t show that there is no “placebo effect” ever.
Medication doesn’t heal my peritonis… Only surgery does the trick, ergo, Medication does not have any effect on anything.
see the wrongness here ?
Me thinks placebo effect can have an effect, even measurable. Sometime it is because the symptoms are psychosomatics, sometimes because the “mind, thinking it will be healed, goes into a “positive” mindset which increase self-healing” …Etc
best regards.
You seem to be disagreeing, does that mean you interpret my post as saying that this study disproves any kind of placebo effect?
Of course if you know of evidence of a placebo effect for other conditions that’s consistently better than doing nothing AND is not about subjective impressions of the patient then I’d be very interested in the info.