On the main page, a list of “myths” is accompanied by text stating that “If these myths were true, chiropractic would have disappeared long ago, just like bloodletting and countless other ineffective procedures.” This seems to assume that human beings are rational and would abandon therapies not shown to work. I also think that it assumes that (to pick just two of the stated “myths”) if chiropractic was unscientific (it is) or if chiropractic was a remedy that relied on the placebo effect (it is in some cases at least) then, being rational creatures, humans would have rejected chiropractic and moved on. Presumably, this assumed rationality of people would also mean that a branch of alternative medicine that relied to a large extent on remedies containing no active ingredient would also have disappeared – but I note that homeopathy is still with us. Perhaps those using homeopathy or chiropractic don’t realise the unscientific (or pseudoscientific) nature of the theorised mechanisms of action proposed for these treatments? Perhaps they are not well versed in the placebo effect, or regression to the mean – and perhaps they find it dfficult to distinguish causation from correlation or coincidence?
Are human beings rational? No. Stuart Sutherland managed to write an entire book on the Irrationality of people. In his introduction, Sutherland writes that his purpose is to “demonstrate that people are very much less rational than is commonly thought and to set out systematically why this is so”. Sutherland points out that no-one (including himself) is exempt. I suggest that anybody who doubts that people are irrational creatures read the book. There are, incidentally, chapters in the book headed Ignoring the Evidence, Distorting the Evidence, Misinterpreting the Evidence, and Mistaken Connections in Medicine. I have previously provided recommended reading for chiropractors and included Sutherland’s book in my suggestions. Here are some “morals” suggested at the end of the chapters of the book I referred to above:
- Search for evidence against your own beliefs.
- Don’t distort new evidence: consider carefully whether it could be interpreted as disconfirming your beliefs rather than supporting them.
- Be wary of your memory: you are likely to recall whatever fits with your current views.
- Beware of being influenced by any explanations you may have concocted in support of your own beliefs.
- […] Don’t trust small samples.
- Beware of biased samples.
Chiropractic Isn’t Scientific: Myth?
Now for the two “myths” I specifically mentioned earlier: chiropractic isn’t scientific and chiropractic results are just the placebo effect. As to the first of these, the link provided goes to a page headed “Chiropractic is Evidence Based”. Apparently, chiropractic is evidence-based: “Because it’s based on the scientific fact that the nervous system controls and regulates virtually every cell, tissue, organ and system of the body.” The nervous system controlling and regulating cells, tissues, organs, and systems does not mean that spinal manipulation can successfully treat a variety of ailments. This is simply a massive non-sequitur.
Helpfully, the page also claims (a) that there is a wealth of evidence that chiropractic is based on and (b) that “research [documents] the results of chiropractic care on asthma, infantile colic, immune function, dysmenorrhea (menstrual cramps), improving vision and brain function, lower back pain, one’s overall health status and many others”. Let’s take a look at the evidence for chiropractic care in treating the first two conditions listed (asthma and infantile colic), seeing as these chiropractors seem to be so confident that the research supports their position.
The BCA earlier this year released a list of studies that they claim support chiropractic treatment of infantile colic. David Colquhoun has an overview of these studies here and he found that the studies referred to included trials that were unblinded or had no control group, a report of two case studies, and a preliminary study into osteopathic (not chiropractic) treatment. Colquhoun points out that “What they don’t do is mention any of the papers that contradict their claims.” Which is not only something that Stuart Sutherland warns of in his book Irrationality, but it also something that does not fit with the claim that chiropractic is evidence-based – Colquhoun refers to Sackett (as do the BCA): “Evidence based medicine is the conscientious, explicit, and judicious use of current best evidence” and goes on to point out that “that means all the evidence”. He also specifically asks “why, for example, is there no mention of Olafsdottir et al. (2001)” [note: the link is to a PDF].
Evidence Matters, meanwhile, examined the evidence for chiropractic treatment of paediatric asthma. Here, we discover that “The BCA’s citations for paediatric asthma list studies that are variable in quality. Although it is accurate to say that there is some evidence of scrutiny and therefore more than a jot of (unspecified quality) evidence, it seems that it is aspiration rather than good scientific evidence that supports the BCA’s claim for a role for the chiropractic element of interventions to manage childhood asthma.” It is also reported that the BCA “has not acknowledged those reviews and studies that report results that do not support their claims: reviews and studies that are uniformly of a much higher standard than most of the evidence that they do cite.” [My italics.]
Are there any other reasons to believe that chiropractic is unscientific? Well, yes – as noted on the Wikipedia page for chiropractic: “Traditional chiropractic assumes that a vertebral subluxation or spinal joint dysfunction interferes with the body’s function and its innate intelligence, a notion that brings ridicule from mainstream science and medicine.” [link] As for the claims to be evidence-based, there is a post on Holford Watch that argues that “the BCA’s approach both fails to be EBM and fails to offer a good alternative”, while I have previously noted that the GCC require “that all provision of chiropractic care must be evidence based”, but believe that craniosacral therapy and applied kinesiology fall under the definition of evidence-based.
Chiropractic Results Are Just The Placebo Effect:
Over a thousand words into this post and I’ve yet to tackle the second myth I mentioned. This is taking longer than I thought. The page on the placebo “myth” begins by arguing that “Some dismiss the results our patients receive as merely the placebo effect. These cynics virtually ignore the mind/body connection that most forward-thinking health care experts are finally recognizing.” This statement seems at first sight to be an admission that chiropractic is a placebo treatment and that critics are wrong to dismiss the results because the expectation and conditioning involved in the placebo effect are so strong*. It appears, however, that the authors are arguing that chiropractic is not a placebo – they write that “chiropractic care regularly helps newborns, infants and even horses and house pets for which the power of the believing mind is clearly not a factor”. It is though, contrary to the assertions of these chiropractors, quite possible for an ineffective treatment to appear to benefit children and/or animals, firstly because there may be an expectation on the part of the owner or medical practitioner that the treatment will be beneficial and secondly because there may be a conditioning effect on the animal being treated.
If chiropractic really did work in children or animals then this would be easily tested in trials designed to reduce bias. In fact, it has been – and these well-designed trials have often failed to find a benefit above placebo from chiropractic treatment of children for several conditions.
Take, for example, nocturnal enuresis: AP Gaylard looked at the evidence for chiropractic treatment of nocturnal enuresis and concluded that this was a case of bedwetting bogosity (“There is no good evidence outside of the chiropractic literature and the two trials that made it into the Cochrane review are essentially negative and of poor quality”).
Or we could use infantile colic as an example: David Colquhoun found that of the studies into chiropractic treatment for colic, the evidence cited by the BCA as being positive was of extremely poor quality and noted that they ignored one study that, in his words, “is one of the few really good papers in the area”. The study compared chiropractic treatment to a placebo treatment and the authors concluded that “Chiropractic spinal manipulation is no more effective than placebo in the treatment of infantile colic. This study emphasises the need for placebo controlled and blinded studies when investigating alternative methods to treat unpredictable conditions such as infantile colic”. If, as chiropractors argue, there can be no placebo effect in children then why was a placebo treatment found to be as effective as chiropractic treatment in this study?
A Cochrane review of manual therapy for asthma, meanwhile, found that of two chiropractic trials “The methodological quality of one of two trials examining chiropractic manipulation was good and neither trial found significant differences between chiropractic spinal manipulation and a sham manoeuvre on any of the outcomes measured” and as Evidence Matters noted of the BCA’s positive evidence for chiropractic treatment of paediatric asthma “those reviews and studies that report results that do not support their claims […] are uniformly of a much higher standard than most of the evidence that they do cite”.
*Note: there is a paper in the New England Journal of Medicine that concludes that there is “little evidence that placebos in general have powerful clinical effects.” NEJM placebo paper [PDF].