I don’t have the time to dig right now, for I remembered seeing studies that measured the “placebo effect” in at least two ways :
The placebo effect is proportional to the expected effect. If you give, as painkiller, a placebo saying it is paracetamol it’ll have lower effect than if you give the same placebo saying it’s an opiate derivative.
The placebo effect depends of the mean of usage : a placebo pill will have less effect than a placebo injection, and a placebo sweet syrup will have less effect than a placebo bitter syrup.
If those two kind of studies are real, how do you account for them ?
Another point : there is also the nocebo effect, where people expecting side-effects of drugs do show some of them when taking a “placebo”. What’s your stance on that ?
Verbal self-reports of pain sensations are especially susceptible to expectancy effects: if I think I’m getting a painkiller, I might well report less pain than I actually feel.
I don’t doubt that this is a “real” effect but we still have to distinguish pain vs. suffering, the objective and subjective components; as the saying goes “pain is inevitable, suffering is optional”. So, I readily grant that some suffering is manipulable through expectancy effects. But there might exist better, more effective ways to alleviate suffering.
To me this still doesn’t justify, e.g. selling sugar at a hundred times its market price.
As for “injection has a larger effect than pills”, for instance, I doubt the strength of the data. The Wikipedia entry on placebo references a single 1961 article for this assertion, and the article would be ideal for this purpose since it focuses on an objective outcome measure (systolic and diastolic pressure) rather than subjective pain assessment.
But the Wikipedia commentary falls straight into a classic mistake of statistical inference: it confuses a difference of significance between two groups (the injection and oral placebo groups) with a significant difference. The oral placebo didn’t show a statistically significant effect and the injection group did: this doesn’t mean that there is a statistically significant difference between the two groups.
The citation for “acupuncture has a stronger effect than a pill” is to a Kaptchuk study that measured self-reported pain levels, so to me it’s only saying “there is a stronger expectancy effect from having needles stuck into you than from taking a pill”, which isn’t earthshaking. Tellingly, the objective outcome measures (e.g. grip strength) showed no significant differences—my arm may feel better with needle treatment but it doesnt work better.
I’m not finding a citation for the bitter vs sweet thing in a quick Google search.
It’s been claimed that color matters, but the one literature review I’ve looked at found these effects “inconsistent” across the studies examined. The studies were of poor quality in general and measured different things so a meta-analysis is not possible. Annoyingly the review reports things that strike me as irrelevant such as “the perceived action of different coloured drugs” which basically consists of asking people what they think a red drug will be most effective for. To me this sounded like a desperate bid to convince readers that “research contributing to a better understanding of the effect of the colour of drugs is warranted”, the conclusion of the abstract. Sigh.
There are a multitude of such effects listed in The Strange Powers of the Placebo Effect, which is a truly amazing video on the subject. Unfortunately, it doesn’t dive into details and doesn’t seem to have much in the way of citations. I would agree that the effects it describe cause problems for the argument in the article.
To add a bit more information, this book covers a number of studies on the placebo effect (since the citations are in the book, which I do not have access to now, I don’t know where to find the original studies.) These studies indicate that the strength of the placebo effect also varies according to the color of the medicine, with different colored pills acting as more effective placebos for different ailments, and that the placebo effect can outweigh the actual effects of a drug (so that a small dose of vomit-inducing medicine could cause less vomiting than the control group, which received no medicine, if offered as an anti-nausea medicine.)
Note that that study doesn’t itself have anything directly to do with the placebo effect. They made fake pictures of boxes of pills, with different colours, and asked people questions like “What do you think this drug would be used to treat?” and “How effective would you expect it to be?”. They didn’t give any drugs (real or fake) to anyone.
(That isn’t intended as a criticism of the study: it’s fine that it wasn’t studying the placebo effect—nor of acephalus’s citation of it: it does indeed have some relevant references. Just a cautionary note.)
I think there are two slightly different definitions of ‘placebo’ here, what we might call the ‘strong’ and ‘weak’ placebo effects.
The weak placebo effect, the existence of which I don’t think anyone denies, is that for phenomena which are largely mental in nature, in particular pain, the mere belief that treatment has happened is enough to ease symptoms.
The strong placebo effect, for which as far as I’m aware there is no evidence whatsoever, but which is the basis for much of so-called ‘evidence-based medicine’, is the claim that, for example, we have to compare new cancer drugs to a placebo because a placebo might cause some shrinkage of the tumour. This is, frankly, nonsense.
It is not correct that “we have to compare new cancer drugs to a placebo because a placebo might cause some shrinkage of the tumour”. (That would indeed be nonsense.)
Rather, it is warranted to compare the effect of a drug against a placebo because the improvements measured in patients taking the drug could be artifactual rather than real—they would have gotten better anyway. The placebo controlled design therefore constitues a severe test of the drug’s effectiveness.
In cancer trials, I understand placebos are rarely used (but gaining favor apparently); instead, the control group is given a different cancer drug, one which is known to work. The null hypothesis is “the new drug isn’t more beneficial than the old drug”.
It is not nonsense. Immune response is affected by a patient’s psychological state of mind.
The reason for cancer trials comparing against other cancer drugs has more to do with 1) those trials being part of costly clinical trials that aim for FDA/European approval which needs comparative data and 2) ethic board approvals being contingent on cancer patients not being treated on just placebo in any case.
Also, no such thing as objective pain. The patient may lie about the severity of the discomfort, but if he successfully convinces himself he’s feeling better, he is feeling better.
Lastly, most of your sources make no claim such as “no such thing as a placebo effect”. If you disagree with claims of strong placebo effects, you may find support for the inverse claim, but that would be “the placebo effect is not strong”, not that it doesn’t exist in the first place.
For a DIY, if you don’t have qualms about that sort of thing, give your ailing grandma a sugar pill some time, tell her it’s some leftover pain medication. See for yourself what happens. (Disclaimer: On second thought, don’t do this. There could be a significant nocebo effect involved.)
Incidentally, it is an ubiquitous occurance that patients report feeling the effects of medication long before it has even passed their liver. For relief of subjective symptoms, there is no deeper objective level. Compare Tinnitus treatment. As for cause-and-effect: If you give a pill and there is a shift in the patient’s subjective experience strictly depending on having taken that pill, that’s as much cause and effect as it gets.
Immune response is affected by a patient’s psychological state of mind.
I have come across, but have yet to investigate fully, claims that immune response can be manipulated through classical conditioning. One book claims this as a placebo response mechanism. This is a much narrower claim than “affected by a patient’s psychological state of mind”.
The patient may lie about the severity of the discomfort, but if he successfully convinces himself he’s feeling better, he is feeling better.
That was not the case in the acupuncture study mentioned earlier: patients reported feeling better, but they were still experiencing reduced grip strength. They were feeling subjectively better, but that was at odds with a functional measurement of their condition.
Conditions requiring medical treatment are not, to my knowledge, exclusively subjective. Tinnitus is very much involuntary, and responds to lidocaine (including in placebo-controlled trials conducted after it was observed that tinnitus patients also “respond” to placebo). In other words, people are not able to convince themselves that their tinnitus is gone, but lidocaine can manage that, at least temporarily.
claims that immune response can be manipulated through classical conditioning. One book claims this as a placebo response mechanism. This is a much narrower claim than “affected by a patient’s psychological state of mind”.
Hence my using the broadest category, leaving open the specific etiology of such an effect. “Can be affected by a patient’s psychological state of mind” is necessarily a less burdensome assertion than “can be manipulated through classical conditioning”, because the former is true if the latter is true, but not vice versa (not iff).
They were still experiencing reduced grip strength. They were feeling subjectively better, but that was at odds with a functional measurement of their condition.
I’m not making the claim that placebo works for objectively quantifiable symptoms that aren’t subject to the perception of the patients. Discomfort, however, is.
Conditions requiring medical treatment are not, to my knowledge, exclusively subjective.
There are indeed kinds of e.g. tinnitus that have a component that can be objectively measured. However, if placebo can effectively treat subjective components, that in itself would justify their usage. For many disease complexes, medication will only address partial symptoms. Which is fine. No need for a panacea.
Of course there in an involuntary cause to subjective symptoms, at least involuntary to a first approximation. The effectiveness of placebos does not preclude the effectiveness of other, actual medicine, such as lidocaine. Also, effectiveness implies only a reduction, not a cessation (“not able to convince themselves that their tinnitus is gone”)
Damn, after all this tinnitus talk now I’m cognizant of my own tinnitus. Better take another sip of my, um - (suspending disbelief) - “special” water.
Note that I don’t believe this is limited to cancer trials. Ethical considerations mean that in any situation where a treatment is known to be effective, withholding it would be wrong, so the most effective drug must be competed with. In addition, the goal of a new drug is to be better than its competitors, and comparing it to a placebo wouldn’t help with this
I don’t have the time to dig right now, for I remembered seeing studies that measured the “placebo effect” in at least two ways :
The placebo effect is proportional to the expected effect. If you give, as painkiller, a placebo saying it is paracetamol it’ll have lower effect than if you give the same placebo saying it’s an opiate derivative.
The placebo effect depends of the mean of usage : a placebo pill will have less effect than a placebo injection, and a placebo sweet syrup will have less effect than a placebo bitter syrup.
If those two kind of studies are real, how do you account for them ?
Another point : there is also the nocebo effect, where people expecting side-effects of drugs do show some of them when taking a “placebo”. What’s your stance on that ?
Verbal self-reports of pain sensations are especially susceptible to expectancy effects: if I think I’m getting a painkiller, I might well report less pain than I actually feel.
I don’t doubt that this is a “real” effect but we still have to distinguish pain vs. suffering, the objective and subjective components; as the saying goes “pain is inevitable, suffering is optional”. So, I readily grant that some suffering is manipulable through expectancy effects. But there might exist better, more effective ways to alleviate suffering.
To me this still doesn’t justify, e.g. selling sugar at a hundred times its market price.
As for “injection has a larger effect than pills”, for instance, I doubt the strength of the data. The Wikipedia entry on placebo references a single 1961 article for this assertion, and the article would be ideal for this purpose since it focuses on an objective outcome measure (systolic and diastolic pressure) rather than subjective pain assessment.
But the Wikipedia commentary falls straight into a classic mistake of statistical inference: it confuses a difference of significance between two groups (the injection and oral placebo groups) with a significant difference. The oral placebo didn’t show a statistically significant effect and the injection group did: this doesn’t mean that there is a statistically significant difference between the two groups.
The citation for “acupuncture has a stronger effect than a pill” is to a Kaptchuk study that measured self-reported pain levels, so to me it’s only saying “there is a stronger expectancy effect from having needles stuck into you than from taking a pill”, which isn’t earthshaking. Tellingly, the objective outcome measures (e.g. grip strength) showed no significant differences—my arm may feel better with needle treatment but it doesnt work better.
I’m not finding a citation for the bitter vs sweet thing in a quick Google search.
It’s been claimed that color matters, but the one literature review I’ve looked at found these effects “inconsistent” across the studies examined. The studies were of poor quality in general and measured different things so a meta-analysis is not possible. Annoyingly the review reports things that strike me as irrelevant such as “the perceived action of different coloured drugs” which basically consists of asking people what they think a red drug will be most effective for. To me this sounded like a desperate bid to convince readers that “research contributing to a better understanding of the effect of the colour of drugs is warranted”, the conclusion of the abstract. Sigh.
There are a multitude of such effects listed in The Strange Powers of the Placebo Effect, which is a truly amazing video on the subject. Unfortunately, it doesn’t dive into details and doesn’t seem to have much in the way of citations. I would agree that the effects it describe cause problems for the argument in the article.
To add a bit more information, this book covers a number of studies on the placebo effect (since the citations are in the book, which I do not have access to now, I don’t know where to find the original studies.) These studies indicate that the strength of the placebo effect also varies according to the color of the medicine, with different colored pills acting as more effective placebos for different ailments, and that the placebo effect can outweigh the actual effects of a drug (so that a small dose of vomit-inducing medicine could cause less vomiting than the control group, which received no medicine, if offered as an anti-nausea medicine.)
Relevant excerpts on colour and vomit.
And here’s a relevant study on Pharmaceutical Packaging Color and Drug Expectancy which has some references.
Note that that study doesn’t itself have anything directly to do with the placebo effect. They made fake pictures of boxes of pills, with different colours, and asked people questions like “What do you think this drug would be used to treat?” and “How effective would you expect it to be?”. They didn’t give any drugs (real or fake) to anyone.
(That isn’t intended as a criticism of the study: it’s fine that it wasn’t studying the placebo effect—nor of acephalus’s citation of it: it does indeed have some relevant references. Just a cautionary note.)
I think there are two slightly different definitions of ‘placebo’ here, what we might call the ‘strong’ and ‘weak’ placebo effects.
The weak placebo effect, the existence of which I don’t think anyone denies, is that for phenomena which are largely mental in nature, in particular pain, the mere belief that treatment has happened is enough to ease symptoms.
The strong placebo effect, for which as far as I’m aware there is no evidence whatsoever, but which is the basis for much of so-called ‘evidence-based medicine’, is the claim that, for example, we have to compare new cancer drugs to a placebo because a placebo might cause some shrinkage of the tumour. This is, frankly, nonsense.
It is not correct that “we have to compare new cancer drugs to a placebo because a placebo might cause some shrinkage of the tumour”. (That would indeed be nonsense.)
Rather, it is warranted to compare the effect of a drug against a placebo because the improvements measured in patients taking the drug could be artifactual rather than real—they would have gotten better anyway. The placebo controlled design therefore constitues a severe test of the drug’s effectiveness.
In cancer trials, I understand placebos are rarely used (but gaining favor apparently); instead, the control group is given a different cancer drug, one which is known to work. The null hypothesis is “the new drug isn’t more beneficial than the old drug”.
It is not nonsense. Immune response is affected by a patient’s psychological state of mind.
The reason for cancer trials comparing against other cancer drugs has more to do with 1) those trials being part of costly clinical trials that aim for FDA/European approval which needs comparative data and 2) ethic board approvals being contingent on cancer patients not being treated on just placebo in any case.
Also, no such thing as objective pain. The patient may lie about the severity of the discomfort, but if he successfully convinces himself he’s feeling better, he is feeling better.
Lastly, most of your sources make no claim such as “no such thing as a placebo effect”. If you disagree with claims of strong placebo effects, you may find support for the inverse claim, but that would be “the placebo effect is not strong”, not that it doesn’t exist in the first place.
For a DIY, if you don’t have qualms about that sort of thing, give your ailing grandma a sugar pill some time, tell her it’s some leftover pain medication. See for yourself what happens. (Disclaimer: On second thought, don’t do this. There could be a significant nocebo effect involved.)
Incidentally, it is an ubiquitous occurance that patients report feeling the effects of medication long before it has even passed their liver. For relief of subjective symptoms, there is no deeper objective level. Compare Tinnitus treatment. As for cause-and-effect: If you give a pill and there is a shift in the patient’s subjective experience strictly depending on having taken that pill, that’s as much cause and effect as it gets.
I have come across, but have yet to investigate fully, claims that immune response can be manipulated through classical conditioning. One book claims this as a placebo response mechanism. This is a much narrower claim than “affected by a patient’s psychological state of mind”.
That was not the case in the acupuncture study mentioned earlier: patients reported feeling better, but they were still experiencing reduced grip strength. They were feeling subjectively better, but that was at odds with a functional measurement of their condition.
Conditions requiring medical treatment are not, to my knowledge, exclusively subjective. Tinnitus is very much involuntary, and responds to lidocaine (including in placebo-controlled trials conducted after it was observed that tinnitus patients also “respond” to placebo). In other words, people are not able to convince themselves that their tinnitus is gone, but lidocaine can manage that, at least temporarily.
Hence my using the broadest category, leaving open the specific etiology of such an effect. “Can be affected by a patient’s psychological state of mind” is necessarily a less burdensome assertion than “can be manipulated through classical conditioning”, because the former is true if the latter is true, but not vice versa (not iff).
I’m not making the claim that placebo works for objectively quantifiable symptoms that aren’t subject to the perception of the patients. Discomfort, however, is.
There are indeed kinds of e.g. tinnitus that have a component that can be objectively measured. However, if placebo can effectively treat subjective components, that in itself would justify their usage. For many disease complexes, medication will only address partial symptoms. Which is fine. No need for a panacea.
Of course there in an involuntary cause to subjective symptoms, at least involuntary to a first approximation. The effectiveness of placebos does not preclude the effectiveness of other, actual medicine, such as lidocaine. Also, effectiveness implies only a reduction, not a cessation (“not able to convince themselves that their tinnitus is gone”)
Damn, after all this tinnitus talk now I’m cognizant of my own tinnitus. Better take another sip of my, um - (suspending disbelief) - “special” water.
Note that I don’t believe this is limited to cancer trials. Ethical considerations mean that in any situation where a treatment is known to be effective, withholding it would be wrong, so the most effective drug must be competed with. In addition, the goal of a new drug is to be better than its competitors, and comparing it to a placebo wouldn’t help with this