Placebo effect report: chiropractic adjustment

by supposedlyfun3 min read15th Apr 202111 comments

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World Modeling
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Content warning: I accidentally got chiropractic treatment and felt better afterward, and I think talking too much about the placebo effect might be a mild cognitohazard, but less hazardous than not talking about it.

 

This is a story about being treated by a medical practitioner with poor epistemics, and the placebo effect that I experienced despite knowing that her medical treatment is no better than a placebo and has no medically sensible mechanism of action and despite the fact that the intervention consisted of gently tugging on my leg exactly once.

Background

I developed an acute lumbar spasm on one side (7 out of 10 pain on movement) a while back after a heavy weightlifting session.  I went to the ER of the U.S. health system that I belong to.  They prescribed skelaxin and menthol patches and referred me to a doctor at the PT clinic a week later.

By the time of the appointment, the pain was 4 out of 10.  The doctor had me demonstrate the movements that triggered pain.  She stated that the spasm was probably due to an underlying "pelvic misalignment."  Bullshit detector, go!  Please note that I am doing my best to recall what I said--I was on point that day for some reason.

Informed consent (???)

SF: A what?

Doc: Yeah, the muscles around your pelvis are very strong, especially with your back squats [~300 pounds was my 1-rep max at the time, not high among trained members of my age/gender cohort], and if one side is stronger or tighter, they can pull the pelvis out of alignment.

SF: What does alignment mean?

Doc: So your pelvis is made of different bones--

SF: Yes, os coxae, ilium, pubis, ishium, sacrum.

Doc: Right, and they can get misaligned.

SF: So the bones move relative to each other? I thought it was all one big stiff system.

Doc: Yeah, it is. The whole thing gets misaligned.

SF: What does misaligned mean?

Doc: Your pelvis gets rotated.

SF: Like, if I'm looking at myself in a mirror, rotated from that perspective?

Doc: Yes.

SF: Can you see it?

Doc: No, a lot of cases of pelvic misalignment don't show up on an x-ray.

SF: So it's misaligned enough to cause pain but not enough to be visible?

Doc: Yes, it's the most likely explanation [her exact words] for the unilateral pain. That's really unusual.  

SF: So what are you going to do?

Doc: An alignment.

SF: What is that?

Doc: Lie down on your stomach here. [I did.] Now put your hand here [on my lower back] and press down firmly. [I did. She then firmly took hold of my leg, on the opposite side from the pain. By this time, I knew I was dealing with a chiropractic-adjacent person, so I was expecting something massive. But she tugged on my leg toward her, away from my torso, exactly once, with so little force that I thought she was just moving my leg into position for a larger yank.] Okay, you're done.

SF: That's it?

Doc: Yes. You should feel relief in the next hour to two days.

SF: That's quite a range. 

Doc: Different people react differently. Call the front desk if you need to get seen again.

What the hell is an osteopath?

I left, and as I was reading the printout summary of my visit, I saw the doctor's name followed by "D.O."  In the U.S., this is a doctor of osteopathy.  Osteopathy started out, like chiropractic, as totally made-up bullshit about how bone problems (hence osteo-) were the source of all illness, but it's made a large move toward evidence-based practice since then. Many states license osteopaths to do just about everything that a doctor of medicine can do. 

But the stain of the original sin remains on their souls.  Osteopathy's status as bullshit-adjacent attracts healers who think "Western medicine" is suspicious.

I had already researched different back pain treatments and concluded, sensibly, that chiropractic adjustments are no better than a placebo.  Pelvic misalignment, in particular, is woo.  

But did you die?

I started driving to the office. While on the freeway, I was overcome by an extremely strong sensation of well-being.  I have had two comparable experiences in my entire life: One, in middle school, when I briefly experienced what was, subjectively, the sensation of the existence of a personal God watching over me; and two, in my late twenties, when I took 1mg of clonazepam during a borderline panic attack and experienced rapid relief.  I was driving down the freeway, knowing I'd just received sham treatment, and laughing with almost delirious joy at how much better I felt.

The well-being sensation passed after about five minutes.  And the pain subsided to about a 1 of 10: "There is something wrong with me, your back, but it's barely worth talking about."  This reduced pain persisted for several days before returning to a level I would have expected by that point without any additional treatment.

To be clear: There is no evidence that chiropractic adjustments are any better than a placebo at relieving back pain (see, e.g.), and I knew this at the time.  I checked the citations again after this remarkable experience, and it didn't seem to dent it.  The effect lasted for days.

I think this is super fucked up. It wasn't a true aspiring-rationality a-ha moment for me at the time, but it should have been.  (I think this was before I encountered HPMOR.)  The human brain! It's so stupid! 

You felt better; who cares?

I think this points to a tension between epistemic rationality and instrumental rationality.

But more importantly--I think using the placebo effect to treat someone is wildly unethical because it promotes strong irrational belief and lowers the epistemic standards of the community. The practitioner is giving people un-ignorable subjective evidence that a treatment works when they know (or should know...) that it does not work in any meaningful way, and they know that most patients will nevertheless (reasonably?) conclude that it does, and spread that meme.      

And yet naive instrumental rationality would tell me that the treatment works, and works better than skelaxin.  Just do it!  I guess true instrumental rationality would say, "Weigh the treatment benefit to you, and everyone else receiving the treatment, against the epistemic externalities."

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There is no evidence that chiropractic adjustments are any better than a placebo at relieving back pain 

Your link doesn't go to the page about chiropratic interventions in general which is https://www.cochrane.org/CD005427/BACK_combined-chiropractic-interventions-for-low-back-pain and which does suggest that there's a small effect which just isn't stronger then mainstream treatments. 

It wasn't a true aspiring-rationality a-ha moment for me at the time, but it should have been.  (I think this was before I encountered HPMOR.)  The human brain! It's so stupid! 

I don't think that having strong experiences that rival your two most intensive experiences that you didn't expect can be well explained by placebo.

A way to update that fits the data better is that you can't conclude from a few studies that try to standardize an effect and fail to find it that there's nothing happening. 

Knowing things is hard. That both goes for knowing that effects exist and knowing that they don't exist. 

This is a sensible response, probably the ideally correct one, and I appreciate it.

My counter question is: as a limited agent, at what point, if ever, am I justified in writing off (that is, assuming it was a placebo) a treatment with no plausible mechanism of action? I've done mainstream treatments for this spasm as well, without the zany effect, and without the equivalent reduction in magnitude.

From the Bayesian perspective you have a model of the world according to which different treatments have different likelihoods of having effects. Then you pay attention to reality and if reality doesn't behave in the way your model predicts your model has to be updated. That's the core of what epistemic rationality is about, being ready to update when your beliefs don't pay rent. 

If you want to go for the maximum of epistemic rationality, write down your credence for the effects of a given treatment down and then check afterwards how good your predictions have been. That's the way to get a world model that's aligned with empiric reality. 

While doing this it's worth to keep in mind what you care about. One alternative medicine treatment is for example colon cleaning. People who do colon cleaning usually observe that after taking the colon cleaning substance their shit has a particular surprising form. If you were previously skeptical that the treatment did anything, you shouldn't take the fact that your shit now has a surprising form that you didn't expect as evidence that the treatment provides the medical benefits it's claimed. 

There are a bunch of alternative medical intervention that follow the pattern of providing surprising effects which then convince people that the intervention is great while not providing the hoped for benefits. 

When thinking about the issue of chiropratic interventions there's also the question of whether the treated "pelvic misalignment" is the root cause. In the scenario where the "pelvic misalignment" is due to one leg being shorter then the other, it's plausible that the "pelvic misalignment" is going to happen repeatidly in the future if it gets fixed.

Then if you would for example go every month to get your "pelvic misalignment" from the chiropratic that's likely better then pain-killers but it's still not a perfect intervention.

When it comes to working with the body there are a few strains of experts that develop their expertise through trained perception and who mostly work outside of the academia given that the trained expert perception is subjective in nature.  I don't think it's necessary that those experts are able to translate what they are doing concept that break down along lines that can be objectively observed (like x-ray's) instead of subjectively accessed. 

Just like a good musician might not be able to give you an objective model of his expertise doesn't mean that they don't have expertise. 

In general it makes sense to go first for the treatments that you think have the most likely success and then if they don't work depending on how desperate you are down the list to treatments that you believe have a lower chance of success. In practice it makes sense to also factor in what success in a given treatment means, the possible risks of the treatment and the costs. 

>If you were previously skeptical that the treatment did anything, you shouldn't take the fact that your shit now has a surprising form that you didn't expect as evidence that the treatment provides the medical benefits it's claimed.

Isn't this conditional on why you think it would not help? If you believe that is does nothign and therefore doesn't work then it doing a weird thing should make one less sure of any claims which on the balance ignorant 50:50 would be nearer to it working thhan a strong stand against. Yes it is good to focus on does the weird thing help or hinder but surprise about the mechanism is still surprise.

When it comes to popular treatments there are reasons why other people use those treatments. Generally, other people using a treatment is some evidence that it works. If the other people however use the treatment because it produces big effects in short time frames that have nothing to do with health benefits that means them using the treatment is less evidence that it works. 

I do think that in the world we are living there's a sizeable number of approaches in the New Age / alternative medicine category that share "surprising short term effect" + "doesn't uphold promises about long term effects" and that it's useful to warn people about them when you tell them they should be more willing to accept evidence that certain alternative medicine interventions can have positive effects.

I took an LW break for a few days and read the abstract of that Cochrane review. I'm going to go paragraph by paragraph in responding, which sometimes looks aggressive on the Internet but is just me crux-hunting.

From the Bayesian perspective you have a model of the world according to which different treatments have different likelihoods of having effects. Then you pay attention to reality and if reality doesn't behave in the way your model predicts your model has to be updated. That's the core of what epistemic rationality is about, being ready to update when your beliefs don't pay rent. 

Agreed.

If you want to go for the maximum of epistemic rationality, write down your credence for the effects of a given treatment down and then check afterwards how good your predictions have been. That's the way to get a world model that's aligned with empiric reality. 

Agreed. I would do this now in advance of another treatment I suspected was woo.

While doing this it's worth to keep in mind what you care about. One alternative medicine treatment is for example colon cleaning. People who do colon cleaning usually observe that after taking the colon cleaning substance their shit has a particular surprising form. If you were previously skeptical that the treatment did anything, you shouldn't take the fact that your shit now has a surprising form that you didn't expect as evidence that the treatment provides the medical benefits it's claimed. 

"Laughing deliriously" is not a result I would have expected from getting my leg tugged on exactly once, but I understand you (above) to be claiming that the unexpected result is evidence that it was not merely a placebo. I'm not a physiologist, but I can't even begin to think of a reason for leg-tug->delirious-laugh other than "placebo."

There are a bunch of alternative medical intervention that follow the pattern of providing surprising effects which then convince people that the intervention is great while not providing the hoped for benefits. 

This is my understanding as well, and it acts as a global "less likely" coefficient any time I hear any claim made by the alternative medicine community.

When thinking about the issue of chiropratic interventions there's also the question of whether the treated "pelvic misalignment" is the root cause. 

The DO made no claims about what caused the pelvic misalignment (although she speculated that it was because I drive a manual transmission!), only that pelvic misalignment was the cause of the pain. 

In the scenario where the "pelvic misalignment" is due to one leg being shorter then the other, it's plausible that the "pelvic misalignment" is going to happen repeatidly in the future if it gets fixed.

Yes, and grossly/radiographically visible pelvic misalignment is a thing that happens due to legs of different lengths, but you are being too charitable. This DO did not say my legs were different lengths or that the misalignment was grossly visible, and in fact, she claimed that many such misalignments were invisible to x-ray.

Then if you would for example go every month to get your "pelvic misalignment" from the chiropratic that's likely better then pain-killers but it's still not a perfect intervention.

In which case I think a "doctor" or practitioner of any stripe has an obligation to dig deeper for an actual root cause. Who stops at, "Very gently tugging on this guy's leg once a month provides some relief for his back pain that was bad enough that he went to the ER"? I'm not prepared to excuse that level of incuriousness; it causes me to down-update my trust in everything the practitioner says.

When it comes to working with the body there are a few strains of experts that develop their expertise through trained perception and who mostly work outside of the academia given that the trained expert perception is subjective in nature.  I don't think it's necessary that those experts are able to translate what they are doing concept that break down along lines that can be objectively observed (like x-ray's) instead of subjectively accessed. 

I completely disagree. I would expect what you're calling subjective trained expert perception to be constantly subject to all of the following cognitive biases (reading the Wikipedia list) and others I haven't thought of:

Anchoring bias (you learn bullshit in your bullshit school about what causes unilateral back pain, and that's your frame for all unilateral back pain now)

Availability bias (these other biases cause you to remember confirming data, which then...causes you to remember confirming data)

Confirmation bias (you remember everyone who you helped and forget the people you didn't help)

Backfire effect (when someone says you didn't help, you find a way to use that as evidence that your underlying theory is true)

Hindsight bias (when someone has a good result, you believe it was predictable at the time you treated them, which makes you look great in your own mind)

Illusory truth effect/availability cascade (everyone in your professional community says unilateral back pain is caused by pelvic misalignment)

Sunk-cost thinking (you spent a lot of money and professional time learning to tug on people's legs, so you tend to ignore evidence that your entire field is woo, or decide that "Western medicine" is the real villain)

Pareidolia (you perceive important patterns in random noise--cf. study where practitioners can't agree on where a supposed trigger point is)

Salience bias (a patient says you cured their back pain vs. a patient who you never see again and posts on the Internet dragging your entire field)

Summing over all these biases, I have basically no faith at all in subjective trained expert perception of people performing chiropractic/bodywork. Crux: Whether there are reliable studies tending to show that such practitioners have any ability to diagnose/recognize illness conditions better than chance, or that their diagnosis-specific chiropractic manipulations do better than the replacement-level intervention we would expect from "Western medicine" treating the same symptom. No partial credit for "You have a C4-C5 subluxation that won't show up on a CT scan; I prescribe [the same physical therapy you'd get from an MD]."

Just like a good musician might not be able to give you an objective model of his expertise doesn't mean that they don't have expertise. 

Bodywork-expertise claims to have both objective effects on humans and objective models behind those effects. I don't think musicians make similarly specific claims (beyond very general things like "these three notes sound weird because the third one is out of key" or "songs in a minor key tend to feel sad relative to songs in the major key"). Musicians and bodyworkers may both claim "expertise through trained perception," but a musician claiming that is making dramatically weaker factual claims at a dramatically weaker epistemic standard than the bodyworker. 

In general it makes sense to go first for the treatments that you think have the most likely success and then if they don't work depending on how desperate you are down the list to treatments that you believe have a lower chance of success. In practice it makes sense to also factor in what success in a given treatment means, the possible risks of the treatment and the costs. 

Agreed.

I don't believe in chiropractic either, but I go occasionally when I have pains that conventional treatments don't help. It has probably been 20 years since my last visit, but I'd guess there have been 5-10 occasions when I went for 1 or a few sessions. Sometimes things got better faster than I expected, other times it took as long as I expected doing nothing would. 

*The placebo effect is an effect.* There's no reason to refuse to take advantage of it when other things don't seem to be working. The big benefit of the placebo effect is that it has few deleterious side effects, so it doesn't hurt to make use of it, while some drugs aren't nearly as safe.

*The placebo effect is an effect.*

Yes, I guess I'm just wrestling with how it pings both instrumental and epistemic rationality.

There have been quite a few studies that show that people can self-heal in remarkable ways.

Summary article: https://www.medicalnewstoday.com/articles/306437#what-is-the-placebo-effect

Summary of the summary: With three treatment groups, the outcomes for the Active group exceed those taking a sugar pill, which, in turn, exceed those not getting anything. Some studies have even shown that bringing people in, telling them that you are giving them a sugar pill with no medicine, and comparing them to a second group that doesn't get the completely non active pill, the group that is not getting any medicine, but is doing something medicine-adjacent (swallowing a pill) has p<.05 significantly better outcomes.

I don't know what "self-heal" means in your comment. Does that include conditions that go away on their own (episode of acute back pain, say)? In which case, wouldn't it make more sense to call those temporary conditions, rather than conditions which require the intervention of some self-healing mechanism?

The only thing the open-label placebo effect tends to prove, to me, is that the placebo effect is operating at a mind-level much deeper than our rationality efforts can hope to reach. 

"Self-heal" just means the condition was not healed by the intervention of the study. For all we know, the patient took some other drug on their own and that cured things.