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Benedetti on Placebos

There has been an ongoing debate about placebos on SBM, both in the articles and in the comments. What does it mean that a treatment has been shown to be “no better than placebo?”  If our goal is for patients to feel better and they feel better with placebos, why not prescribe them? Do placebos actually do anything useful? What can science tell us about why a patient might report diminished pain after taking an inert sugar pill? The subject is complex and prone to misconceptions. A recent podcast interview offers a breakthrough in understanding.

On her Brain Science Podcast Dr. Ginger Campbell interviewed Dr. Fabrizio Benedetti, a physician and clinical neurophysiologist who is one of the world’s leading researchers on the neurobiology of placebos. A transcript of the interview [PDF] is available on her website for those who prefer reading to listening. The information Dr. Benedetti presents and the expanded remarks by Dr. Campbell after the interview go a long way towards explaining the placebo phenomenon and its consequences for clinical medicine. Dr. Campbell also includes a handy list of references. I’ll try to provide a summary of the main points, but I recommend reading or listening to the original.

A common misconception is that the response to placebos is a purely subjective psychological response involving only the cortical level of the brain; but evidence is accumulating that real, measurable, objective subcortical neurophysiologic phenomena are involved. One of the first hints was a 1978 study showing that the placebo response to pain could be blocked by naloxone, a narcotic antagonist drug, indicating that the placebo must have actually caused an increase in endogenous opioids. (more…)

Posted in: Basic Science, Neuroscience/Mental Health

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Dummy Medicine, Dummy Doctors, and a Dummy Degree, Part 2.0: Harvard Medical School and the Curious Case of Ted Kaptchuk, OMD

Review

The recent albuterol vs. placebo trial reported in the New England Journal of Medicine (NEJM) found that experimental subjects with asthma experienced substantial, measured improvements in lung function after inhaling albuterol, but not after inhaling placebo, undergoing sham acupuncture, or “no treatment.” It also found that the same subjects reported having felt substantially improved after either albuterol or each of the two sham treatments, but not after “no treatment.” Anthropologist Daniel Moerman, in an accompanying editorial, wrote, “the authors conclude that the patient reports were ‘unreliable,’ since they reported improvement when there was none”—precisely as any rational clinician or biomedical scientist would have concluded.

In Part 1 of this blog we saw that Moerman took issue with that conclusion. He argued, with just a bit of hedging, that the subjects’ perceptions of improvement were more important than objective measures of their lung function. I wondered how the NEJM editors had chosen someone whose bibliography predicted such an anti-medical opinion. I doubted that Editor-in-Chief Jeffrey Drazen, an expert in the pathophysiology of asthma, had ever heard of Moerman. I suggested, in a way that probably appeared facetious, that Ted Kaptchuk, the senior author of the asthma report, might have recommended him. (more…)

Posted in: Acupuncture, Chiropractic, Clinical Trials, Health Fraud, Herbs & Supplements, History, Medical Academia, Medical Ethics, Naturopathy, Pharmaceuticals, Science and Medicine, Science and the Media

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Revisiting Daniel Moerman and “placebo effects”

About three weeks ago, ironically enough, right around the time of TAM 9, the New England Journal of Medicine (NEJM) inadvertently provided us in the form of a new study on asthma and placebo effects not only material for our discussion panel on placebo effects but material for multiple posts, including one by me, one by Kimball Atwood, and one by Peter Lipson, the latter two of whom tried to point out that the sorts of uses of these results could result in patients dying. Meanwhile, Mark Crislip, in his ever-inimitable fashion, discussed the study as well, using it to liken complementary and alternative medicine (CAM) as the “beer goggles of medicine,” a line I totally plan on stealing. The study itself, we all agreed, was actually pretty well done. What it showed is that in asthma a patient’s subjective assessment of how well he’s doing is a poor guide to how well his lungs are actually doing from an objective, functional standpoint. For the most part, the authors came to this conclusion as well, although their hedging and hawing over their results made almost palpable their disappointment that their chosen placebos utterly failed to produce anything resembling an objective response improving lung function as measured by changes (or lack thereof) in FEV1.

In actuality, where most of our criticism landed, and landed hard—deservedly, in my opinion—was on the accompanying editorial, written by Dr. Daniel Moerman, an emeritus professor of anthropology at the University of Michigan-Dearborn. There was a time when I thought that anthropologists might have a lot to tell us about how we practice medicine, and maybe they actually do. Unfortunately, my opinion in this matter has been considerably soured by much of what I’ve read when anthropologists try to dabble in medicine. Recently, I became aware that Moerman appeared on the Clinical Conversations podcast around the time his editorial was published, and, even though the podcast is less than 18 minutes long, Moerman’s appearance in the podcast provides a rich vein of material to mine regarding what, exactly, placebo effects are or are not, not to mention evidence that Dr. Moerman appears to like to make like Humpty-Dumpty in this passage:
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Posted in: Acupuncture, Basic Science, Clinical Trials, Neuroscience/Mental Health, Science and the Media

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Belief in Echinacea

Note: The study discussed here has also been covered by Mark Crislip. I wrote this before his article was published, so please forgive any repetition. I approached it from a different angle; and anyway, if something is worth saying once it’s probably worth saying twice.

 

Is Echinacea effective for preventing and treating the common cold or is it just a placebo? My interpretation of the evidence is that Echinacea does little or nothing for the common cold. Initial reports were favorable, but were followed by four highly credible negative trials in major medical journals. A Cochrane systematic review was typically wishy-washy  The Natural Medicines Comprehensive Database rates it as only “possibly effective” commenting that

Clinical studies and meta-analyses show that taking some Echinacea preparations can modestly reduce cold symptom severity and duration, possibly by about 10% to 30%; however, this level of symptom reduction might not be clinically meaningful for some patients. Several other clinical studies found no benefit from Echinacea preparations for reducing cold symptoms in adults or children…

A review on the common cold in American Family Physician stated that Echinacea is not recommended as a treatment.

I have a friend who believes in Echinacea. She says for the last several years she has taken Echinacea at the first hint of a cold, and she hasn’t developed a single cold in all that time. I told her that if that was valid evidence that it worked, I had just as valid evidence that it didn’t. For the last several years I have been careful not to take Echinacea at the first hint of a cold, and I haven’t had a single cold in all that time either. So I could claim that not taking Echinacea is an effective cold preventive! I thought my “evidence” cancelled out hers; she said we would just have to agree to disagree.

A recent study looked at the effect of belief on response to Echinacea and dummy pills. “Placebo Effects and the Common Cold: A Randomized Controlled Trial” was published by Barrett et al. in the Annals of Family Medicine(more…)

Posted in: Clinical Trials, Herbs & Supplements, Science and Medicine

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Dummy Medicines, Dummy Doctors, and a Dummy Degree, Part 1: a Curious Editorial Choice for the New England Journal of Medicine

Background

This post concerns the recent article in the New England Journal of Medicine (NEJM) titled “Active Albuterol or Placebo, Sham Acupuncture, or No Intervention in Asthma.” It was ably reviewed by Dr. Gorski on Monday, so I will merely summarize its findings: of the three interventions used—inhaled albuterol (a bronchodilator), a placebo inhaler designed to mimic albuterol, or ‘sham acupuncture’—only albuterol resulted in a clinically important improvement of bronchial airflow; for that outcome the two sham treatments were equivalent to “no intervention.” For all three interventions, however, self-reported improvements were substantial and were much greater than self-reported improvements after “no intervention.” In other words, dummy treatments made the subjects (report that they) feel better, whereas real medicine not only made them feel better but actually made them better.

Before proceeding, let me offer a couple of caveats. First, the word ”doctors” in the flippant title of this post refers mainly to two individuals: Daniel Moerman, PhD, the anthropologist who wrote the accompanying editorial, and Ted Kaptchuk, the Senior Author of the trial report. It does not refer to any of the other authors of the report. Second, I have no quarrel with the trial itself, which was quite good, or with the NEJM having published it, or even with most of the language in the article, save for the “spin” that Dr. Gorski has already discussed.

My quarrels are the same as those expressed by Drs. Gorski and Novella, and by all of us on the Placebo Panel at TAM. This post and the next will develop some of those points by considering the roles and opinions of Moerman and Kaptchuk, respectively.

A True Story

Late one night during the 1960s a friend and I, already in a cannabis-induced fog, wandered into a house that had been rented by one of his friends. There were about 8-10 ‘freaks’ there (the term was laudatory at the time); I didn’t know any of them. The air was thick with smoke of at least two varieties. After an uncertain interval I became aware of a guy who was having trouble breathing. He was sitting bolt upright in a chair, his hands on his knees, his mouth open, making wheezing sounds. He took short noisy breaths in, followed by what seemed to be very long breaths out, as though he was breathing through a straw. You could hear the wheezing in both directions. Others had also noticed that he was in distress; they tried to be helpful (“hey, man, ya want some water or somethin’?”), but he just shook his head. He couldn’t talk. My friend, who had asthma himself, announced that this guy was having an asthma attack and asked if he or anyone else had any asthma medicine. No one did.

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Posted in: Acupuncture, Cancer, Clinical Trials, Energy Medicine, Faith Healing & Spirituality, Health Fraud, Homeopathy, Medical Academia, Medical Ethics, Naturopathy, Pharmaceuticals, Public Health, Science and Medicine, Science and the Media

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“CAM” Education in Medical Schools—A Critical Opportunity Missed

Mea culpa to the max. I completely forgot that today is my day to post on SBM, so I’m going to have to cheat a little. Here is a link to a recent article by yours truly that appeared on Virtual Mentor, an online ethics journal published by the AMA with major input from medical students. Note that I didn’t write the initial scenario; that was provided to me for my comments. The contents for the entire issue, titled “Complementary and Alternative Therapies—Medicine’s Response,” are here. Check out some of the other contributors (I was unaware of who they would be when I agreed to write my piece).

Posted in: Acupuncture, Basic Science, Chiropractic, Energy Medicine, Herbs & Supplements, History, Homeopathy, Medical Academia, Medical Ethics, Science and Medicine

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Placebos as Medicine: The Ethics of Homeopathy

Is it ever ethical to provide a placebo treatment? What about when that placebo is homeopathy? Last month I blogged about the frequency of placebo prescribing by physicians.  I admitted my personal discomfort, stating I’d refuse to dispense any prescription that would require me to deceive the patient. The discussion continued in the comments, where opinions seemed to range from (I’m paraphrasing)  “autonomy, shmatonomy, placebos works” to the more critical who likened placebo use to “treating adults like children.”  Harriet Hall noted,  “We should have rules but we should be willing to break them when it would be kinder to the patient, and would do no harm.” And on reflection, Harriet’s perspective was one that I could see myself accepting should I be in a situation like the one  she described. It’s far easier to be dogmatic when you don’t have a patient standing in front of you. But the comments led me to consider possible situations where a placebo might actually be the most desirable treatment option. If I find some, should I be as dogmatic about homeopathy as I am about other placebos?

Nicely, Kevin Smith, writing in the journal Bioethics, examines the ethics of placebos, based on an analysis of homeopathy. Homeopathy is the ultimate placebo in routine use — most remedies contain only sugar and water, lacking a single molecule of any potentially medicinal ingredient. Smith’s paper, Against Homeopathy — A Utilitarian Perspective, is sadly behind a paywall.  So I’ll try to summarize his analysis, and add my perspective as a health care worker who regularly encounters homeopathy.
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Posted in: Homeopathy, Medical Ethics

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SBM at TAM9

This year The Amazing Meeting 9 (designated TAM9 From Outer Space) will be held in Las Vegas from July 14-17. If you have not registered, do it fast – this year the conference will likely sell out.

Among the many incredible speakers and events at TAM9 there will be a Science-Based Medicine workshop and an SBM panel discussion. The prominence of SBM at TAM9 partly reflects the new collaboration between SBM and the James Randi Educational Foundation (JREF), who organizes TAM.

The SBM website is now a joint project of the New England Skeptical Society (who founded SBM) and the JREF – two non-profit educational organizations dedicated to promoting the public understanding of science. I am delighted that the JREF is making SBM a priority, and we all look forward to working closely with them in promoting high standards of science in medicine and improved public understanding of the relationship between science and the practice of medicine.

As part of this new relationship I have accepted a position at the JREF of Senior Fellow and Director of their Science-Based Medicine project.

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Cochrane is Starting to ‘Get’ SBM!

This essay is the latest in the series indexed at the bottom.* It follows several (nos. 10-14) that responded to a critique by statistician Stephen Simon, who had taken issue with our asserting an important distinction between Science-Based Medicine (SBM) and Evidence-Based Medicine (EBM). (Dr. Gorski also posted a response to Dr. Simon’s critique). A quick-if-incomplete Review can be found here.

One of Dr. Simon’s points was this:

I am as harshly critical of the hierarchy of evidence as anyone. I see this as something that will self-correct over time, and I see people within EBM working both formally and informally to replace the rigid hierarchy with something that places each research study in context. I’m staying with EBM because I believe that people who practice EBM thoughtfully do consider mechanisms carefully. That includes the Cochrane Collaboration.

To which I responded:

We don’t see much evidence that people at the highest levels of EBM, eg, Sackett’s Center for EBM or Cochrane, are “working both formally and informally to replace the rigid hierarchy with something that places each research study in context.”

Hallafrickin’loo-ya

Well, perhaps I shouldn’t have been so quick to quip—or perhaps that was exactly what the doctor ordered, as will become clear—because on March 5th, nearly four months after writing those words, I received this email from Karianne Hammerstrøm, the Trials Search Coordinator and Managing Editor for The Campbell Collaboration, which lists Cochrane as one of its partners and which, together with the Norwegian Knowledge Centre for the Health Services, is a source of systematic reviews:

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Placebo Effect for Pain

It has long been recognized that there are substantial multifactorial placebo effects that create real and illusory improvements in response to even an inactive treatment. There is a tendency, however (especially in popular discussion), to oversimplify placebo effects – to treat them as one mind-over-matter effect for all outcomes. Meanwhile researchers are elucidating the many mechanisms that go into measured placebo effects, and the differing magnitude of placebo effects for different outcomes.

For example, placebo effects for pain appear to be maximal, while placebo effects for outcomes like cancer survival appear to be minimal.

A recent study sheds additional light on the expectation placebo effect for pain. The effect is, not surprisingly, substantial. However it does not extrapolate to placebo effects for outcomes other than pain, and the results of this very study give some indication why. From the abstract:

The effect of a fixed concentration of the μ-opioid agonist remifentanil on constant heat pain was assessed under three experimental conditions using a within-subject design: with no expectation of analgesia, with expectancy of a positive analgesic effect, and with negative expectancy of analgesia (that is, expectation of hyperalgesia or exacerbation of pain).

What they found was that the positive expectation group reported twice the analgesic effect as the no expectation group, and the negative expectation group reported no analgesic effect. This is a dramatic effect, but not surprising.

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