Risks of CAM Part One: Nocebo

August 25, 2010 at 6:30 pm (Alternative Medicine, Chiropractic, Nutritionism, Patrick Holford, Placebo) (, , , , , , , )

Risk of adverse effects from (mis)information

As well as relying on the placebo effect when making claims of the efficacy of their therapies, those providing alternative treatments may also be aided by something akin to the nocebo effect. If you tell healthy people they are sick (or sick people that they are sicker than they thought), it may be possible to induce the perception of symptoms that you can later claim to have resolved.

I’ve recently seen an example of a chiropractor being disciplined by the General Chiropractic Council, partly for making alarmist statements. [Note – link goes to PDF.] The chiropractor was found guilty of Unacceptable Professional Conduct and suspended from the statutory Register of Chiropractors for two months. Here’s the GCC’s summary of the alarmist statements:

Patient A explained that she wanted only one or two treatments because she could not afford more. In response Dr Stefan made alarmist statements i.e. if Patient A did not agree to the number of recommended treatments she could be caused long-term irreversible problems.

About two weeks later Patient A asked for her treatment sessions to be reduced from three to two per week because of her financial circumstances. Dr Stefan responded with further alarmist statements i.e. if Patient A did not get her spine corrected properly now she risked long-term problems and she’d possibly be in a wheelchair when she was older

The alarmist statements, which conveyed a level of risk that was disproportionate to Patient A’s condition, made Patient A anxious

If I was told that I faced irreversible problems that might lead to my being unable to walk then I think I would feel very anxious indeed. I might also perceive a worsening of my symptoms. If you tell someone they are ill (or that they are sicker than they realised) I think it’s possible that you may be setting up a self-fulfilling prophecy. You can then treat them and leave them in the same condition as when they first consulted you, but having perceived an improvement.

Body in Mind have some discussion of more chiropractic fearmongering in the form of a leaflet. Having pointed out that information should be accurate and empower the patient to make good decisions, Body in Mind go on to claim that the problems with the patient information form are legion:

The patient is led to consider their pain as the result of serious spinal malalignments (subluxations). Subluxations are a common focus of some chiropractic practice. However the evidence that such subluxations exist and are clinically important phenomena does not stand up to close scrutiny. [Note: previous link goes to PDF. See also Zeno and Skeptic Barista for more on the death of the subluxation.]

There is also the implication that these subluxations may be causing disease of other biological systems (once again in the absence of evidence or a clear and plausible mechanism). […] Ultimately by perpetuating these myths about back pain the patient is given good reason to fear the pain as a marker of serious disease; to somatize, catastrophise and alter their behaviour to protect their spine unnecessarily.

In their Epilogue, Body in Mind note that their concerns regarding the information sheet “are related to how it could promote false and unhelpful illness beliefs and a reliance on unnecessary therapy in patients with normal benign back pain” and go on to point out a “more sinister side” to the story.

It’s also possible to make up new conditions. For example, histadelia. Patrick Holford’s book Optimum Nutrition for the Mind (ONM) includes information on a condition known as histadelia.

First, you have to pay for the test – it will cost you £55 if you want to know whether the Orthomolecular Medicine crowd thinks you have high histamine. This FftB info pack [Note: link goes to PDF.] includes prices for tests. Once you have been “diagnosed” as histadelic, you will then require treatment for your condition.

There seems to be no good evidence that the condition known as histadelia is actually a problem for anyone (I can’t find any evidence it actually exists). I know of no evidence that the test for histadelia is useful. Neither is there evidence that the remedies for histadelia (vitamins and minerals, natch) work.

What is the scientific evidence for Holford and Pfeiffer’s belief that histamine is a real condition, that can be accurately diagnosed and treated by pills? I don’t know. Despite Patrick’s famous referenciness, the section of his book Optimum Nutrition for the Mind that deals with histadelia has no references. That’s right, not one single reference to back up the claims of these advocates of Orthomolecular Medicine. He cites a single case study, quotes some opinions from Carl Pfeiffer and speculates about Marilyn Monroe being high histamine.

Holford recommends… pills. And lots of them. Two grams of Vitamin C, 15mg of Zinc, 5mg of Manganese, at least 50mg of Vitamin B6. If you are “experiencing undesirable symptoms”, Holford expects you to fork out for more pills: 500mg Calcium and 500mg Methionine twice daily.

A genuine nocebo effect

As Tim Minchin once wrote, alternative medicine is that which “has either not been proved to work, or been proved not to work”. [Link goes to Youtube vid.] Homeopathy falls into the latter category, but can an inert treatment such as homeopathy have perceived side-effects? I thought the answer would be “yes”, but the available evidence seems to suggest that this may not be the case. It looks like I was, once again, mistaken.

As well as perceived benefits from an inert treatment, there may be perceived side-effects. These side-effects would be a consequence of exposure to the inert treatment, but would not have arisen due to physiological effects of said treatment.

Ben Goldacre has some discussion of the nocebo effect and homeopathy here, and includes a link to this paper. The authors:

…found that the rate of adverse events in the placebo arms of trials with anti-migraine drugs was high. In addition, and most interestingly, the adverse events in the placebo arms corresponded to those of the anti-migraine medication against which the placebo was compared.

Of specific relevance to homeopathy and the nocebo effect is this systematic review by Grabia and Ernst. While adverse events in the placebo arms of trial of drugs that actually work are high (at least in the case of trials of anti-migraine drugs), the same does not appear to be true of homeopathy:

In total, 50 aggravations were attributed to patients treated with placebo and 63 to patients treated with homoeopathically diluted remedies. We conclude that this systematic review does not provide clear evidence that the phenomenon of homeopathic aggravations exists.

It almost seems as if homeopathy does literally nothing. No effects, no side-effects. Nothing. I guess it shouldn’t be surprising that a ‘remedy’ containing nothing should have no side-effects, but it still surprised me.

The lack of side-effects due to the inert treatment in question is perhaps not entirely helpful to homeopaths. As Ben Goldacre points out:

…the best moment [of the parliamentary Science and Technology Select Committee’s review] was Dr Peter Fisher from the Royal London Homeopathic Hospital (funded by the NHS) explaining that homeopathic sugar pills do actually have physical side effects: so they must be powerful.

Critical Self-Appraisal

Ben Goldacre has written of the “long, strong, justified, and brutal tradition of critical self-appraisal” which distinguishes medicine from quackery. Here, the authors of a paper on the nocebo effect and generic substitution argue that:

On the basis of the studies analysed, the conclusion can be drawn that the nocebo effect can play a crucial role in the treatment of psychological diseases. Therefore, physicians and pharmacists should be responsible to prevent the nocebo effect through adequately educating the patients.

Similar calls from those involved with complementary and alternative medicine (journals, practitioners etc) for CAM practitioners to be responsible in trying to prevent such harms as may result from advice disseminated in the course of their practice would be welcome. As would the dissemination of advice based on the best available evidence.


I have written about histadelia before, so rather than rewrite my thoughts have simply copied and pasted from my previous post. I’m pretty sure that it’s OK for me to plagiarise myself, but I thought I should mention it.


  1. davidp said,

    G’day. The first paragraph of the “A genuine nocebo effect” section is confusing.
    “… but can an inert treatment such as homeopathy have perceived side-effects? I thought the answer would be “yes”, ” … “It looks like I was, once again, mistaken” but then you discuss adverse events in the placebo arms of trials.

    Are you saying that you knew placebos can have perceived side-effects, and so expected homeopathy to have them too, but it doesn’t ? Presumably this is partly because there are few patient expectations of side effects from homeopathy, whereas real medicines have listed side effects and the placebos produce these effects too.

  2. jdc325 said,

    Presumably this is partly because there are few patient expectations of side effects from homeopathy, whereas real medicines have listed side effects and the placebos produce these effects too.

    I wish I’d written that.

    Thanks for commenting David.

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