The Placebo Effect

[HansMustermann]

Actually, if a person in pain is given a placebo as a pain killer it can reduce their pain. This is true even if the person knows it is a placebo!

Ref: https://www.health.harvard.edu/mental-health/the-power-of-the-placebo-effect

Sort of. Placebo seems to make a measurable difference when the effect is self-reported. Like, yes, for pain. Or for how long it takes to fall asleep, and pretty much anything else. You tell a bunch of people that they should feel better if they take that pill, a bunch of them will dutifully feel a need to tell you that they did.

When you have SOME objective way of measuring whether someone actually got better, strangely that effect disappears. Oh they'll tell you they're feeling better, are coughing less, etc, but if you measure it, statistically, as a group they really don't fare any better than the guys that were told to just suck it up. If they had a flu, it will actually last just as long with a placebo as with nothing at all. (Again, speaking statistically, as a group.) Otherwise that Onion article would be reality rather than satire. If prescribing some sugar pills actually made the flu heal faster, we'd actually prescribe it.

Randi himself was talking about basically the same effect when he was talking about debunking faith healers. People were going on stage and being told that Jesus cured them of diabetes, they'd throw away their pills, swore they felt better, etc. And when you checked on them later, they died. Presumably while being convinced to the bitter end that they're feeling better, or they would have started taking their pills again. Meanwhile the objective outcome tells you that no, they were actually doing a lot worse.


IMHO that looks suspiciously like the known effect where people tell you what they think you want to hear in anonymous polls. Including stuff like that, all else being equal, more will answer "yes" than "no" at the same question, if you phrase it positive or negative. Or picking the first answer more than the last one in multiple choices. That's why polls are randomized.

Or such effects that if you ask a question in a group setting and several paid actors in the group all say the same obviously wrong answer, the rest of the group (the actual subjects of that study) also start to pick that answer.

Or that in police lineups, if there's ANY hint that the cops prefer one guy over the one you actually saw, people start identifying that one. Just the cops seeming to look more at one guy than the others can start to skew the results.

Humans are social animals, and most try to be agreeable, really. It colours so many interactions that frankly, it would be more surprising if reporting placebo results were somehow the only domain where somehow it doesn't apply.

 

[angrysoba]

Yeah, it might be more helpful to know what exactly we are talking about (although perhaps that is part of the overall problem of talking about placebos).

It seems to me that there is a plausible mechanism for saying that someone can have reduced subjective feelings of pain, etc... when a placebo is applied.

If we are talking about, say, people's cancer going into remission because of a placebo, then that would stretch credulity a lot more.

Similarly, when it comes to nocebos, perhaps someone having their attention drawn to something and being told that it ought to cause pain, may end up having that effect.

As an example, I sometimes listen to a podcast by two doctors who talk about powerlifting, and they say that the nocebo effect can come in when people are told that their posture is wrong, or that an X-ray shows something that should cause a lot of pain, and that they need to make "corrections". In those situations, it is argued that people start to feel pain that wasn't there before because their doctor told them they should.

 

[Roger Ramjets]

Mike Hall on that podcast has talked about it a lot and presented evidence that the papers purporting to show a powerful placebo effect don't actually say that.

They do though, sort of.

To which Conover asks:

When they do that, they found that, in some cases the placebo surgery is as strong or beats the real surgery? Is that what you’re saying?

And Hall responds:

It doesn’t beat [it], there was no statistically significant difference between the sham surgery and real surgery.

Conover is astonished:

Wow! That goes way beyond what I and I think most people think of the placebo effect as being capable of.

So what does Conover's 'astonished' conclusion mean? That in this case the 'sham' surgery was just as effective as the 'real' surgery. Or IOW, the 'real' surgery was just was just as ineffective as the 'sham' surgery.

The message being missed here is that some 'real' medicine is actually quite useless. Considering all the downsides of surgery, this suggests that a lot of harm is being done to placate patients' desires to get their medical problems 'fixed' when in many cases the body will repair itself given time.

But there's another effect that isn't being talked about - the 'knowledge' effect.

One Christmas my father came to visit me, but it was not a happy time. On the day he arrived he started suffering from severe pains in his legs. He saw a doctor about it, but whether he didn't listen or the doctor didn't explain it properly, it didn't help. So he went to another doctor who did explain it properly, and advised him to lie down on a flat board for several days.

That fixed the problem, which had nothing to do with his legs. He actually had 'bone spurs' in his spine, which were pushing on the nerves coming from his legs. Knowing what is actually wrong can help the patient to act in ways that aid their recovery and/or manage their pain. It's often easier to handle pain if you know it it isn't serious, could be reduced by being aware of what is causing it, and will go away with time.
We all know this, but how many of us race to the doctor asking for something to 'fix' the pain so we don't have to deal with it? Not me. I see the doctor to find out what is wrong, and only take medication if it is really necessary. A few months ago I got a severe pain in the left side of my neck that didn't go away. The doctor couldn't find anything seriously wrong and thought I had probably just sprained a muscle. He prescribed pain killers to help get over it, but I didn't take them. Instead I found ways to reduce the pain with posture and exercise.

Today I noticed that the pain has almost gone. If I had taken the pain killers and carried on regardless, it could have become chronic before I knew it. So I put up with a little pain and used it to recover. But the pills were there if I needed them. The best placebo is the one you don't take!

 

[arthwollipot]

Probably everyone else is wrong about the placebo effect, other than this guy.

He says he's not an expert. He avoids being cited for his claims. He eschews scientific peer review. Is it too much to ask that he do some actual science, before we start taking him too seriously?

By this argument, no journalist can ever be taken seriously on any subject, because they are journalists, not scientists or sportspeople or meterorologists or politicians. A journalist exists in order to convey information from specialist fields to a general audience. They do not have to be within the field in order to do this, in fact it's often better if they are not. Sometimes they're good at it, and sometimes they're not.

This probably isn't clear from just this one article, but is clear having listened to six years of the podcast. Mike is not a scientist - he's a web developer - but he's also an amateur journalist. He reports on actual science from peer-reviewed journals. He, like us, is a science enthusiast rather than a scientist, and a lot of what he talks about on the show is how badly science is reported in the mainstream media. For example, the paper he refers to was badly reported by Adam Conover, who is a professional journalist and not an amateur one, as saying that the placebo surgery was just as good as the real surgery, rather than what is actually says, which is that the real surgery was no better than the placebo surgery. By putting this false spin on the paper he feeds into the idea of the "powerful placebo" that works even though it's not a genuine intervention.

When Mike says that his podcast shouldn't be cited as a reference to anything, he's implying that you should cite the actual science, as he does. He is more than forthcoming with links if you ask.

Anyway, if you actually click on the link I gave you, you'll notice a link to the paper being referenced, which is this one. Genuine peer-reviewed science from The Lancet, so you can check it out for yourself if you want.

For those allergic to links, here's the full conclusion:

In conclusion, we showed that, in patients with persistent subacromial shoulder pain due to impingement, improvement in Oxford Shoulder Scores with arthroscopic subacromial decompression did not differ to that achieved with arthroscopy only (placebo surgery). Although both types of surgery provide greater symptom improvement than no treatment, this difference was of uncertain clinical significance. The findings (which should be communicated to patients during the shared treatment decision-making process) question the value of this type of surgery for these indications, and might discourage some surgeons from offering decompression surgery and dissuade some patients from undergoing the surgery.

 

[arthwollipot]

Sort of. Placebo seems to make a measurable difference when the effect is self-reported. Like, yes, for pain. Or for how long it takes to fall asleep, and pretty much anything else. You tell a bunch of people that they should feel better if they take that pill, a bunch of them will dutifully feel a need to tell you that they did.

When you have SOME objective way of measuring whether someone actually got better, strangely that effect disappears. Oh they'll tell you they're feeling better, are coughing less, etc, but if you measure it, statistically, as a group they really don't fare any better than the guys that were told to just suck it up. If they had a flu, it will actually last just as long with a placebo as with nothing at all. (Again, speaking statistically, as a group.) Otherwise that Onion article would be reality rather than satire. If prescribing some sugar pills actually made the flu heal faster, we'd actually prescribe it.

Yes, exactly. The "powerful placebo" effect is most visible in studies of pain, for example, for which there is no way to objectively measure it so there is no choice but to rely on the patients' self-report. They may actually think that they are feeling less pain than prior to the placebo, or they may just say so because they expect that this is what the doctor wants to hear.

But as Hans says, when you do have some way to objectively measure outcomes, the effect disappears. Another study that Mike reported on in another episode and which I assume will make an appearance as an article, is an asthma study that clearly showed that effect. Patients reported improvement when objective measurements showed none.

 

[WhatRoughBeast]

When I was quite young, our family would take a couple of weeks to visit my aunt and uncle in Nova Scotia. This was quite a drive in those days, and I got carsick.

Mother Sills' Seasick Pills were what we used, and on one trip we ran out. My parents stopped at a small-town pharmacy, and bought what was available - not Mother Sills'. I was dubious, but my mother assured me that the new pills would work.

"How long will it last, Mommy?"

My mother, being a woman of wit and intelligence, looked at the label and said,

"Six months."

It worked, too.

So, yeah, I do believe in the Placebo Effect.

 

[Ziggurat]

Sort of. Placebo seems to make a measurable difference when the effect is self-reported. Like, yes, for pain. Or for how long it takes to fall asleep, and pretty much anything else. You tell a bunch of people that they should feel better if they take that pill, a bunch of them will dutifully feel a need to tell you that they did.

When you have SOME objective way of measuring whether someone actually got better, strangely that effect disappears.

Pain is subjective, so that doesn't really tell us anything useful about placebo's effects on pain. The view that pain is simply a sensory indication of damage, so that if you fix the damage you fix the pain, is actually wrong. Pain is actually much more complex, and much more mental, than most people give it credit for.

 

[HansMustermann]

I have no doubt that some people even convince themselves that they're feeling less pain, if that's what they want to believe or feel a peer pressure to believe. I mean, if nothing else, those guys Randi mentioned that died after they threw away their actual medicine after seeing a faith healer, must have actually been convinced they feel better with the placebo than even with actual medicine, or they would have started taking their pills again.

BUT, and it's a big fat BUT: does that mean that they ACTUALLY feel less pain, like this is often claimed? How would you know?

When you do objective measurements, like for lung capacity in asthma, you have hard numbers to compare. Like, this exact number of cubic centimetres now, vs that other exact number of cubic centimetres last month. And they've been written down on paper, or in a file on the computer. You don't rely on just vaguely remembering that the piston kind went about yay high last month.

But with pain it's exactly just relying on people's fallible memory of something that was never actually quantized. They're not comparing some number now vs what number they remember from last month, but some subjective sensation that is not even a constant, but fluctuates based on everything from time of day, temperature, what you're doing at the moment, etc.

Essentially, think of trying to describe to someone exactly how much something hurts, so they can compare it to how much their problem hurts. Yeah, exactly. You can't. You can't even think of where to start. Now think of describing it to yourself, so you can compare it with exactly how much it hurts next week. Yeah, you can't actually do that either.


And I'm speaking from actual experience too. I actually have some messed up joints that cause me pain now and then. Occasionally extreme pain. It's just how it is when you get older.

But let's say my wrist started to hurt like hell again. Well... how would I even know if it hurts objectively more or less than last time? Hell, if someone gave me a placebo, how would I know if it actually hurt more or less than last week? I don't have any numbers to remember and compare for it. It's a subjective sensation that I couldn't memorize an exact copy or value of even if I tried.

And I've even seen myself fall for placebo. Like, I was having extreme pain at work and had forgotten my Ibuprofen at home, and the HR lady gives me some supposedly great pill that a doctor friend of hers gave her for her shoulder pain. And I take it, and think, man, yeah, this is way better than my Ibuprofen. This is working great. Then I inquire aand... yeah, it's the exact same Ibuprofen I had at home, and in exactly as many milligrams per pill, just a different brand and pill shape

 

[Ziggurat]

BUT, and it's a big fat BUT: does that mean that they ACTUALLY feel less pain, like this is often claimed? How would you know?

Yes, it does mean that. That's my whole point. The science of pain is complex, but we know that pain is far more brain-centered than previously believed, and there are very strong feedback loops for pain. Stress is a major component of those feedback loops. Believing you feel less pain will reduce stress and make you actually feel less pain.

 

[HansMustermann]

But again, as long as all you can rely on is some people's self-reporting how can you actually know?

I mean, sure, you can point at studies where people say they're feeling better or worse, but then see that asthma study where people said they can breathe better, even though when you measured it, they actually couldn't.

Plus, you can see the same effect in pretty much everything else, not just pain inputs.

E.g., you get people swearing that music sounds better with some placebo audiophile cable. Or someone on a forum long ago was swearing MP3s sounds better from some hard drive brands than from others. Once he had convinced himself that they use different magnetic coatings, and way back different cassettes with different magnetic coatings reproduced different frequency ranges, it stood to reason that different hard drives would reproduce different ranges in the same MP3 files too. And he could actually hear the difference, being the super-audiophile that he thought he was.

Or people have been shown to swear that the reflections and shading look better on computer B, if you tell them that computer A has RTX off and B has RTX on, when actually both are off. And it's not even just about RTX. As far back as different graphics chips were a thing, people could and would swear that graphics looked better on, say, a Matrox card than on an nVidia card. Even though if you showed them two screenshots in the same place, it was 50-50 if they can tell which is from which card. Bonus points if it was both on the same cards, but some could still clearly see a difference in what they thought was from their favourite card. Hell, this was the bread and butter of ye olde 3dfx fanboys vs nvidiots flame wars.

Or, hell, it doesn't even have to be sensory inputs. There is actually a discussion RIGHT NOW on modthesims.info about how some mod makes some people's The Sims 3 game load faster, even though it physically can't do that, and if you take a stopwatch to it, it doesn't. We're not even talking about some different processing signals from nerve endings. It's the time interval in which that loading bar fills up on the loading screen. But if people convince themselves that it loads faster, then they'll swear it does. And there are similar talks on the various modding boards about similar wrong perceptions of all sorts of things in all sorts of games. People can swear that the AI is better, when they installed a mod that doesn't affect the AI, for example.

So yeah, that's how ridiculously far the placebo effect actually goes. It affects not just what your sensory nerve endings perceive about your own body, but even how you perceive what's happening on your computer.

Etc.

So essentially what I'm asked to believe is this: while relying on people's memory and subjective comparisons of sensations is provably wrong when you can actually measure it, nope, it is always 100% objective reality when you can't measure it.

 

[Pixel42]

I don't often get headaches, but when I do I take paracetamol, which I've found to be effective.

A while back I had a headache whilst my sister was staying, and she saw me take the paracetamol. Later she asked me if the headache was better, and I had to stop and think in order to find out. I realised that I had simply stopped paying attention to the pain, probably soon after I took the pills. In order to find out if it had gone, I first had to pay attention to it again.

We know our brains can "tune out" noises and smells etc - the sensory input is still there, but it is no longer being brought to the attention of our conscious awareness because it isn't important. That's the root cause of confirmation bias, of course. If we paid attention to everything our senses are telling us all the time we'd go mad, so our unconscious minds filter it, and only bring the important stuff into awareness.

So I'm wondering if at least part of the placebo effect is our unconscious minds simply tuning out minor symptoms because we've done something about them (taken a pill), so there's no reason our unconscious minds need to keep bringing them to our attention. Once I took the paracetamol I simply stopped thinking about the pain, whereas before it was pretty much all I was thinking about.

I find the same thing with tinnitus, which I've had for some years - I only notice it if I actually think about it, the rest of the time I must simply be tuning it out.

Of course when the symptom gets worse, tuning it out becomes harder and harder. But it seems to be minor, chronic, symptoms that the placebo effect works best for - for a given value of "works".

 

[arthwollipot]

So I'm wondering if at least part of the placebo effect is our unconscious minds simply tuning out minor symptoms because we've done something about them (taken a pill), so there's no reason our unconscious minds need to keep bringing them to our attention. Once I took the paracetamol I simply stopped thinking about the pain, whereas before it was pretty much all I was thinking about.

Undoubtedly. But it's also, as I said, uncontrolled variables. It's also the idea that you take a pill when the pain is worst, but because you take it when it's at the top of the bell curve, as it were. The pain goes down not because of the intervention, but because it was going to go down anyway.

This and a host of other factors contribute to the "powerful placebo" effect.

 

[steenkh]

I believe we are putting too much thought into this. Everybody agree that placebo has an effect in some cases, but claiming that placebo does not exist because these cases can also be explained by misdiagnosis, bias, etc. is after just a description of placebo itself. It is like saying medicine doesn’t exist because it is paracetamol etc that does the work.

Placebo is not a “thing” in itself, it is the difference in effects between taking a certain cure and not taking the cure - under conditions controlled to make the subject unaware if the cure is taken or not.

The “placebo effect” is the difference between knowing that you take a cure and actually taking a cure. In this case controlled by removing any known beneficial cure so that it is purely the belief that a cure is administered that is tested.

There can be many explanations why the belief that a cure is administered can have an effect, but this does not make this effect disappear.

Any real cure will have the element of belief that the cure is administered (or it would be like secretly adding something to a patient’s food), so the placebo effect is always present even when there are real effects.

 

[arthwollipot]

There can be many explanations why the belief that a cure is administered can have an effect, but this does not make this effect disappear.

Except that in the asthma study, the effect does disappear.

 

[Chanakya]

Actually this was a cool thread, at least as far as I'm concerned. Thanks to arthwollipot for bringing this up.

I'd always thought placebo was the mind-body thing. A psychosomatic kind of effect that is, in this case, beneficient. (It can also be negative, in which case nocebo.) At least that was my impression.

I see now, basis this thread, that placebo's basically one of three things, not just the one. First, a catch-all for all kinds of uncontrolled variables. Two, the mind tuning out, so that the baleful effects of some ailment appears to have improvement, even though there's been no real improvement as measured objectively. And three, the psychosomatic thing. (Although: Is the psychosomatic thing even a thing at all? Does that actually happen, the mind thinks you're getting better, so the body does get better, to an extent? The comments on this thread seem to indicate not.)



Also, two observations:

(1) Like I'd said earlier, the design of the study referenced in the OP seems glaringly shoddy. (Said as an absolute amateur, open to being corrected if someone knows better.) They've got three groups, two of which improved somewhat as a result of post-op physio apparently (one with real surgery, one with sham surgery), compared to the third group that had no surgery and no post-op physio. Whoever designed this thing, shouldn't they have had the wits to fit in some equivalent physio in the third group as well (call it something else, since it can't be called "post-op" physio), so that you're comparing apples with apples?

(2) Somehow in these studies, they're kind of blinkered, it seems to me. I mean, intervention gives better result than no intervention, but the intended intervention gives no better result than the placebo intervention. So what do you do? Conclude your intervention is no good, and move on. But shouldn't you be doing something else? Given that there has been some improvement vis-a-vis no intervention, then shouldn't you be exploring how that improvement happened? Call it placebo, call it catch-all variables, whatever, but shouldn't you be exploring that, whatever the hell it is? Because the ultimate aim is surely not just to test some specific intervention, but to actually get some intervention that works, right?

... in this case the 'sham' surgery was just as effective as the 'real' surgery. Or IOW, the 'real' surgery was just was just as ineffective as the 'sham' surgery.

The message being missed here is that some 'real' medicine is actually quite useless. Considering all the downsides of surgery, this suggests that a lot of harm is being done to placate patients' desires to get their medical problems 'fixed' when in many cases the body will repair itself given time.....

Like I was saying, while sure, one takeaway is that the 'real' surgery is no better than the sham surgery, but another takeaway, and the more important takeaway, is, or should be, that surgery (whether real or sham, and everything that goes with it) is somehow somewhat better than no surgery at all. Therefore what that "somehow" is, that makes this better (probably physio, in this case), surely that is what is really interesting here? And surely investigating that should be the next step now, in cases like this?

I speak without first-hand knowledge of the research process, only a cynical but TBH uninformed impression about how these things happen, but I'd guess the people pouring research dollars in are usually interested only in how some surgery or some molecule performs. More mundane stuff like those "other variables" don't promise good returns, and so aren't bothered with --- while, conceivably, similar improvements recorded with the intended intervention would've got them all excited and happy. (If true, this suggests a change might be called for as far as how these research goals are set, basically.)

 

[theprestige]

But again, as long as all you can rely on is some people's self-reporting how can you actually know?

Since all pain is self-reported to begin with, how can you actually know they were in pain in the first place? When it comes to the study of pain, all we have to work with is self-reporting. Might as well ask if the "green" that you see happens to be the same color as the "green" that I see.

 

[Ziggurat]

But again, as long as all you can rely on is some people's self-reporting how can you actually know?

I mean, sure, you can point at studies where people say they're feeling better or worse, but then see that asthma study where people said they can breathe better, even though when you measured it, they actually couldn't.

Plus, you can see the same effect in pretty much everything else, not just pain inputs.

In all the examples you are referring to, there is a distinction between the experience and the underlying thing that is being experienced. And you keep pointing out that the underlying thing being experienced isn't any different, even if the experience is different because people have fooled themselves.

But pain IS the experience. The underlying thing being experienced isn't pain, but physical damage. And yes, we know placebos don't affect physical damage to the body. That doesn't mean they don't affect the experience. If you think it affects the experience, guess what? It does. By definition.

So essentially what I'm asked to believe is this: while relying on people's memory and subjective comparisons of sensations is provably wrong when you can actually measure it, nope, it is always 100% objective reality when you can't measure it.

You are being asked to believe that people's perceptions of pain IS the pain, that pain isn't anything else. The proper comparison to all your examples would not be asking people how much pain they suffered, but how badly their body was damaged. And yeah, people won't get that right. But since the challenge we're talking about isn't fixing damage but alleviating pain, then their experience is rightly front and center.

 

[Ziggurat]

We know our brains can "tune out" noises and smells etc - the sensory input is still there, but it is no longer being brought to the attention of our conscious awareness because it isn't important. That's the root cause of confirmation bias, of course. If we paid attention to everything our senses are telling us all the time we'd go mad, so our unconscious minds filter it, and only bring the important stuff into awareness.

In the case of pain, it goes even deeper than that. It isn't simply that the brain stops paying attention to some constant level of nerve signals. The signaling actually go both ways. The brain can actually tell the nerves to become more or less sensitive. So tuning out the signals can actually lead to fewer signals being sent.

 

[WhatRoughBeast]

... Might as well ask if the "green" that you see happens to be the same color as the "green" that I see.

I beg you, don't go there.

You are now talking about qualia, we are deep in Philosophy territory.

 

[theprestige]

By this argument, no journalist can ever be taken seriously on any subject, because they are journalists, not scientists or sportspeople or meterorologists or politicians.

Now you're speaking my language!