Revisiting placebo

Aug 16 2010 Published by under [Medicine&Pharma], Medicine

The New England Journal of Medicine recently published a troubling article on acupuncture, which was ably deconstructed by Dr. Mark Crislip. This incident has reignited a discussion of what, exactly, "placebo" is.

A common argument is that placebo is like any other intervention, something that can be intentionally harnessed for the benefit of patients.  This is both true and overly simplistic.

First, we must review what "placebo" is.  There are basically two primary uses of the word.  The first is technical.  In randomized controlled trials, making sense of an intervention requires some sort of control group.  If I give Fabulostatin to one group, any changes I see in the group may be due to chance alone or to bias.  I can minimize this effect by subjecting a similar group to an identical-appearing sugar pill, one which we call a "placebo".  If the only significant difference between the two groups is Fabulostatin or placebo then significant differences between the two groups can be more readily attributed to Fabulostatin.

This doesn't mean that the placebo group will be unchanged.  If there is a third arm of the study, one in which no pill was given, we can often measure a difference between this group and the placebo group.  This difference is usually called the "placebo effect", that is, the group that is treated with a sugar pill improves despite being given no active drug.The second use of the word is in a therapeutic sense.  A doctor may give a patient a pill or treatment they know to be essentially inert, but then give the patient the explicit expectation that it will help them.  The patient may indeed feel better.  This is a tricky concept, one that is difficult to measure.  It is also ethically problematic.

There is little doubt that a visit to a physician is more than just a trip to a drug dispensary.  Simply visiting a compassionate doctor can improve subjective measures of health.  But can this be harnessed in a more specific way?  According to this study, yes. But the truth is rarely this simple.

Most studies that claim to use the placebo effect as a therapy (including the study in NEJM) have a few things in common.  They confound the two main meanings of placebo, and they evaluate subjective measures of self-limited conditions.  One way to look at low back pain, for example, is that medical science is not very effective.  Most interventions, including anti-inflammatory medications, back exercises and physical therapy, are not much more effective than doing nothing.  Most low back pain, even severe low back pain, resolves over the course of several weeks, no matter what intervention we use.  The use of placebo (whether we call it a sugar pill, or acupuncture, or chiropractic) fails to improve on the natural course of the disease.  When we administer "placebo" to these patients, it is tempting to take credit for their improvement, but all we've really done is let nature take its course.  Sometimes this is a good thing; if we help steer a patient away from back surgery when they don't need it, we've helped protect our patient from harm.  But this is qualitatively different from "doing something".

There are significant ethical problems in using an inert treatment and taking credit for its "success".  Medical ethics (at least in North America) generally frown on deception.  Deception removes a patient's ability to give informed consent for a treatment and creates a destructive doctor-patient relationship.  If I lie about a sugar pill, why should the patient trust me about a blood pressure pill?

Ethical problems aside, placebo isn't a therapy in the same sense as surgery or medication.  It is the sum of many otherwise-intangible effects, such as being listened to, touched, and cared for.  There is no need to add needles, back-cracking, or sugar pills.  It's time to give up the idea that we can ethically prescribe placebo treatments.  Prescribing therapies that are "as good as placebo" simply creates deception, cost, and possible harm through the application of physical interventions that cannot improve upon holding a patient's hand and listening to them.

25 responses so far

  • T. Diane Peters says:

    Have you ever HAD acupuncture? I can assure you, it has an effect. It is an active treatment. It's not the same as doing "nothing". I've worked in biotech for more than 30 years, designing and implementing oncology clinical trials in so I think I know what a placebo is (and isn't). As someone who has had acupuncture a few times over the years for certain conditions I can assure you, it has a beneficial effect. It works better for some things (like chronic or acute pain, or sleep disorders) than for others (metabolic or immune conditions). To say it is harmful, or deceptive is incorrect. It has many beneficial effects, including a sense of well-being, temporary relief of pain, improved sleep -- but without side effects. How could that be harmful? Here's an important point: the vast majority of people who have acupuncture treatment are ALSO being treated by their western medicine doctors at the same time. Very few people abandon western medicine in favor of acupuncture. Crislip's diatribe was very defensive in its tone and I had to wonder why he was so strident in his attack. He can keep saying acupuncture doesn't work, but that doesn't make it so.

  • SurgPA says:

    Ms. Peters,

    Ah, the fallacy of the anecdote: "as someone who had acupuncture a few times... I can assure you it works." Does your definition of acupuncture include the concept of meridians, or does sticking needles into the skin at random places (ie sham acupuncture) count? Assuming you are not arguing the value of sham acupuncture, can you cite any studies that demonstrate that real acupuncture is better than sham acupuncture? From what I've been able to find, the efficacy of "real acupuncture" is the same as the efficacy of "fake acupuncture." While both provide a small effect on subjective (ie pain, nausea, mood) outcomes, that effect is the very placebo effect of which Pal writes. Unless you can reliably and reproducibly demonstrate that "real" acupuncture provides an effect not seen by sham acupuncture, it is deceptive to tell a patient that acupuncture provides that effect.

    • T. Diane Peters says:

      Again, I ask you, have any of you naysayers ever tried acupuncture? There is a systemic effect; it's doing something. Now, obviously, what it is doing has not been characterized. But that does not mean it's "fake" or a "sham". It means it's not fully understood.

      • James Sweet says:

        My wife tried acupuncture and I was present one of the times. It did indeed seem to have an effect. A relaxing environment, soothing music, incense, personal attention, etc.... Yep. Definitely works to make the patient feel better.

        So would a visit to the spa.

        Then again, my insurance will cover acupuncture with a co-pay, but not a visit to the spa... so maybe there is value to this whole thing after all!

    • T. Diane Peters says:

      Also, I've only been to licensed acupuncturists. I've been to 3 over them over the past 10 years or so. All have treated me in a consistent manner. A licensed acupuncturist will not promise "cures" and the ones I've dealt with have been very straightforward about what they can help and what they cannot help. One of them even works in the oncology clinic at the local university medical center (it's a world-famous teaching hospital in California). I don't think in this day and age of budget cuts etc. that she would be working there -- as an acupuncturist -- if she were not providing some meaningful help to patients with subjective conditions such as nausea, pain, and mood. It appears that in some places, like the UK, acupuncture is not regulated and anyone can do it. However, in California, anyway, that is not the case; they must be licensed, pass state exams, etc., so there are professional in their approach and quite knowledgeable about disease states, likelihood of success, etc. So, at the very least, not all acupuncturists are not equal in training, experience, and practice, so it may not be possible to generalize. Now, you may be interested in the fact that I do feel that chiropractors are worthless. I saw one once and she was indeed a charlatan.

      • Dr Technical says:

        The main issue with acupuncture is that there is no proven increased efficacy between acupuncture done by a "professional" where the needles are placed in supposedly important places, and sham acupuncture, whereby needles are placed in any old place.

        In both cases patients report the same effects; these are generally short term and are probably a combination of placebo effect endorphin like highs from having needles stuck in the patient.

        In any article like the one above you are bound to get "but it worked for me" anecdotes. It really is pointless recounting such stories. The only reliable way to work out whether a medical procedure works or not is a proper medical trial, and when these are done on acupuncture the results are at best up in the air.

  • Scott_SGG says:

    Instead of using a different, but equally clunky, way to initiate a placebo-type pain reduction (or other effect), is there any thought to getting to the heart of what the placebo effect actually is, biologically speaking?

    I remember seeing some documentary (might have been a discussion with Dawkins and someone else - real researcher, not a quack I think) where it seemed there is real study into the actual pathways that are induced during the placebo effect, regardless of what method is used to stimulate it. (1) I think this was specifically about pain relief effects, and (2) I can't remember if this was solid stuff or still speculative.

    But if - *if* - there are pathways, say in the brain, that are activated which may result in the actual relief of pain wouldn't that indicate a more legitimate line of study: Developing compounds (or something) which activate the pathway directly, thus leading to the desired effect without sugar pills or other fakery?

    • Schwa says:

      Assuming a physiological response beyond the psychological benefit of someone caring about you and doing something to help you out, the most likely explanation would be endorphin release from getting stuck full of needles. It turns out that we have drugs that activate the same pathways: opiates.

      But even if we assume away all the problems with placebo like subjects reporting improvement because they want to please researchers, short-term satisfaction from positive attention, etc., there's no reason to believe that acupuncture does anything that a massage doesn't (and the massage carries a much smaller risk of infection).

      • Scott_SGG says:

        Just so I'm clear, I wasn't asking my question to subtly imply, or weasel in, that acupuncture or massage or anything is somehow actual medicine because of whatever may be going on in the body.

        I was asking because of the reasons I stated:
        (1) While,hypotheses such as yours are fine, and could well be the case, I'm simply curious if anyone has actually found data related to the biological processes (*if any*) that may be behind some forms of placebo effect,
        and, if so,
        (2) is it possible there is a way - a non-fakery, actual biological/medical way - of targeting said pathways in a reproducible fashion, followed by standard trials, etc, that could actually be used as a real, science-based method of pain control that has not yet been explored.

        As for point (1), I guess I should just look for myself to see if there is any such data - guesses don't cut it.

  • JJM says:

    @T. Diane Peters, Have you ever had bloodletting? I can assure you that it works! Centuries of testimonial such as yours prove it.

    A colleague of mine likes to say that health research only began to progress when we realized how we can fool ourselves and started doing controlled experiments. In properly-done experiments, acupuncture is no better than placebo; which is to say it is ineffective. (I cannot understand how you can do the work you claim, and not understand that.)

    • T. Diane Peters says:

      Acupuncture has only recently been investigated and is not fully understood. Many aspects of medicine are like that. I suspect that because it's an ancient practice, and because it comes from a nonwestern culture, it is much easier to dismiss it out of hand. I guarantee that if someone at, say, Harvard, "discovered" acupuncture in 1990, we'd all be very excited about it. Also, you needn't insult me re: the bloodletting comment. That was unkind and uncalled for.

      • Vicki says:

        We don't need to "fully investigate" something to measure whether it works. Aspirin was demonstrably useful against pain and fever before anyone understood the biochemistry. And if something doesn't work, asking how it works is chasing a unicorn up a blind alley: you might as well ask why New Hampshire is a monarchy.

        Lots of people have gotten excited about acupuncture, for a wide variety of uses. Some of them said "hey, stick needles in me," and some others started measuring the effects of doing so. Unfortunately, acupuncture doesn't work.

        At best, licensing requirements mean your acupuncturist won't give you hepatitis or any other serious disease in the course of taking your money to stick needles in you. (When I pay someone to do that, the needles are carrying ink, but your kink is okay.) Following a prescribed training course doesn't mean you'll get anything useful out the other end. It can mean you waste time and money, or worse: you can practice an exercise in a way that increases your chance of injury, for example.

      • JJM says:

        @T. Diane Peters, My comment about bloodletting was unkind; but your assertion of authoritative understanding of clinical research, following your anecdote about acupuncture, insulted my intelligence. If you understood clinical research, you would know the value of anecdotes. You would be better-off if you presented yourself as the mere believer that you are. I have been a scientist for a really long time, and I can sniff-out pretenders.

  • palmd says:

    There is nothing particularly ancient about acupuncture (link). Even if it were ancient, that would not be a valid argument for its use.

    To say that it is "not fully understood" is the wrong question. The correct question is "can it be shown to work". So far, its been show to work as well as randomly poking someone with small wooden sticks. That's not terribly impressive.

  • stripey_cat says:

    From the realm of n=1 samples, I suspect that you need to believe that acupuncture works for it to have an effect - my DBf tried it for spinal arthritis (he'd been told that the only option was surgery, and to quote the surgeon "you still have the use of your limbs"), and had no effect at all, beyond mild discomfort from lying still for too long, and some skin irritation. However, he was very doubtful of the efficacy going in. On the other hand, if you give someone adrenaline, they have a measurable response whether or not they believe in it.

  • DrP. says:

    On the example of back pain treatments as a placebo,
    speaking purely from a theoretical perspective, the main flaw in the argument present here;
    that most treatments ( both conventional and non-convetnional )have the same outcome as a placebo and that most occurrences are gone after some days,
    is that while the symptom of back pain is one effect, the cause of that pain maybe due to one or many of several possibilities - therefore a treatment for the pain, if not treating the appropriate cause for that particular case - could on average be the same as a placebo.

    I am using the back pain as an example argument, but this can be true for many illnesses.
    Accurate diagnosis is not always so definitive even with state of the art methods.
    Take for example anti-drepression drugs, the large number the wide ranging side effects, the by and large lack of efficacy from a random sample of patients.

    To summarise: without a well defined problem and most medical issues are not well defined, our determination of what is a placebo effect or what is not a placebo effect can rarely be assigned in a clear case by case manner.
    That is why most drugs go through a large scale testing - so that by chance, on average the drug seems to give an improvement.

    We humans do have medical science successes and improving all the time, but often it is a medical chance, and we can but live with it.


    • JJM says:

      Michael, you were doing alright till you got to "... most drugs go through a large scale testing – so that by chance, on average the drug seems to give an improvement." You clearly don't understand clinical research. Large-scale testing is done to reduce the effect of 'chance' on the outcome.

      Acupuncture is not part of medical "science."

      • DrP. says:

        jjm, thank you for you compliments...

        however I will reiterate that large clinical trials while reducing the 'chance' are
        a only necessity because there is a large degree of 'chance' in the outcomes, that needs to be reduced, so we conduct large trials and thereby reduce the chance that the cure is not worst than the cause, ie does not kill
        If we knew, if we knew the outcome as well as we know the outcome if we set a broken leg or design a new laser we would not need animal models and then large scale trials.
        I use the word 'chance' instead of couched in terms of p-scores to emphasize that much of our medical or even social science is empirical and are the best solutions we have to multi-variable problems, but are not in the least definitive.
        Whither we say it is a placebo or non-placebo effect it can be a matter of degree, not yes or no.


        • JJM says:

          @Michael, Perhaps I misunderstood you, I apologize. It seems English is not your first language, and I always allow language mistakes since I want to encourage all people to join in the discussion. Your first post, while slightly confusing, was not so bad as to be unmistakably a language problem.

  • Nomad says:

    T. Diane Peters:

    You claim background in designing clinical trials, and then you state, essentially, "I felt a result, so therefore I know it has an effect". Do you design clinical trials to look for a single person who thinks the treatment has a positive effect and then stop?

    If you have the background you claim to have, then you know that personal anecdotes are not useful in this kind of discussion.

    Your argument about the ritual of acupuncture not being "nothing" is misplaced at best. You say you're getting needles stuck into you, so therefore this must be something. Of course a sugar pill is also something. A voodoo ritual is clearly something, for that matter. But is it something that causes an actual effect within the body, or is it a ritual that you've been conditioned to believe will cause a vague result that you will therefore experience regardless of the actual physical influence of the process in question?

    The studies done so far show that, while you're happy in only having licensed, "consistent", acupuncture, it needn't be so. The "ancient" tradition of acupuncture is based on the concept of energy lines in the body that has no basis to anything known in reality. In other words, they're imaginary. Trials comparing that method to simply sticking needles in people in no particular pattern, or indeed not even sticking needles in at all and just poking people with toothpicks, can produce similar results, so don't try to tell me that maybe we just don't know about the energy lines yet.

    So your "something" is largely unnecessary. Yet, curiously, belief that you are receiving this "something" may be important. The actual needle penetrating your skin? It can be disposed of. Careful manipulation of energy lines? Not really of any relevance. Thinking that you are having needles stuck into you along mystical sounding energy lines? That part seems to be more important.

    That sounds rather like a placebo to me.

  • Karen says:

    Damn. You-all have talked me out of trying acupuncture. Now get back to work and find some actual treatments, ok? Thanks! 🙂

  • rob says:

    i believe accupuncture was key in preventing me getting h1n1 or other flu this year.

    it must have been a good clinic that i went to cuz they only required one needle and it only took about 3 seconds, then *bam* i was out of there.

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