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The Placebo Effect (The Skeptic's Dictionary)

Orphia Nay

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In the latest Skeptic's Dictionary newsletter, Robert Todd Carroll discusses the placebo effect.

A snippet:

4. What is the definition, in your mind, of the placebo effect?

In my mind? I have an entry on the placebo effect in the SD. I've also recently recorded a podcast on the placebo. The short answer is that there is no placebo effect. This may shock you, but 'the placebo effect' is a catch-all term for a host of things, which I detail in my entry on this topic in the SD.

This clears up some confusion I've had. In the SD entry, which he has just updated, he expands on this:

The placebo effect is the measurable, observable, or felt improvement in health or behavior not attributable to a medication or invasive treatment that has been administered. [new] The placebo effect is not mind over matter; it is not mind-body medicine. 'The placebo effect' has become a catchall term for a positive change in health not attributable to medication or treatment. As is explained below, the change can be due to many things, such as regression to the mean, spontaneous improvement, reduction of stress, misdiagnosis in the first place, subject expectancy, classical conditioning, etc. [/new]

In my many forays at woo forums, they tend to think the placebo effect is a real cure caused by some magical power of the mind.

Bob Carroll goes on:

A person's beliefs and hopes about a treatment, combined with their suggestibility, may have a significant biochemical effect, however. Sensory experience and thoughts can affect neurochemistry. The body's neurochemical system affects and is affected by other biochemical systems, including the hormonal and immune systems. Thus, it is consistent with current knowledge that a person's hopeful attitude and beliefs may be very important to their physical well-being and recovery from injury or illness. But it does not follow from this fact that if the patient has hope will she recover. Nor does it follow from this fact that if a person is not hopeful she will not recover.

(Highlighting is what Bob Carroll has recently added to the article.)

I has the dumb. Could someone clarify that paragraph for me, as the updated section seems to contradict the older section.
 
I has the dumb. Could someone clarify that paragraph for me, as the updated section seems to contradict the older section.

Isn't it self evident? Or am I missing something?

Sure, psychological changes can effect a myriad of hormones, can effect up or down regulation of the receptors of numerous neurochemicals, alter production rates of endogenous psychoactives, change gene expression via methylation of genes or other reactions like acetylization of their protein sheaths; an entire lexicon of biological changes are psychologically induced.

To assume that 'positive' mental processes and the biochemical feedback mechanisms they produce will tend to create an overall 'positive' biochemical change is at the moment pure speculation. Comes down to how you define "positive" and "hopeful" scientifically, in what context and in relation to what.
 
I don't agree entirely with the article content, but only quibbles, so here's my read on the highlighted part.

"But it does not follow from this fact that if the patient has hope will she recover."
- A hopeful outlook can play a role in the healing and recovery process, but that doesn't mean they will necessarily recover just because they're hopeful.

"Nor does it follow from this fact that if a person is not hopeful she will not recover."
- Similarly, lacking a hopeful outlook doesn't mean one will not recover.

Simmered down it means hope is not the key component to healing or recovery.
 
Thanks. I think I'm getting it. Having hope may affect a person's neurochemicals, but there are also other factors at work.
 
I think it's more of a case of the placebo effect altering a person's subjective judgement of their condition rather than the condition itself. If a study is relying on a patient to self-report their symptoms, then this will have a major effect on results.

The same thing with the nocebo effect. People will genuinely suffer headaches, nausea, etc when they mistakenly think they've been exposed to something which will cause these symptoms, even though there is nothing physically wrong with them.
 
I think it's more of a case of the placebo effect altering a person's subjective judgement of their condition rather than the condition itself. If a study is relying on a patient to self-report their symptoms, then this will have a major effect on results.

The same thing with the nocebo effect. People will genuinely [believe they] suffer headaches, nausea, etc when they mistakenly think they've been exposed to something which will cause these symptoms, even though there is nothing physically wrong with them.

Good answer! (Plus my minor, pedantic edit.)
 
An observation, even if false, can certainly manifest biological effects.
If you think you see a lion in your yard, you may get a flush of adrenalin, even if it turns out to be a shadow or a bush.

People that (apparently) get beneficial results from homeopathy are tapping into something similar. A double blind analysis of homeopathy is interesting because it eliminates half of the hopefulness. People that 'believe' are less likely to submit to any testing. Hence, a lot of the nocebo effect has been pre-filtered, and the confirmation bias gets exaggerated.
 
Could someone clarify that paragraph for me, as the updated section seems to contradict the older section.
Here we go:

>it is consistent with current knowledge that a person's hopeful attitude
> and beliefs may be very important to their physical well-being and recovery from injury or illness.
In other words: the placebo effect probably exists and can make a difference.

> But it does not follow from this fact that if the patient has hope will she recover.
> Nor does it follow from this fact that if a person is not hopeful she will not recover.
This statement is true, but not specific to placebo treatments -- it is universal to _all_ medical treatments. You can think of any serious illness and replace the yellow highlighted words with any medical treatment in the world, and the statement remains true. All treatments, including placebo (where measured to have some effect), increase the statistical odds of getting healed. Without a 100% guarantee that getting the treatment will get you healed, nor a guarantee that not getting the treatment (or any treatment at all) will cause you to remain sick for the rest of your life.
 
I feel that a page on the placebo effect is missing the other half the the placebo phenonemon as we know it.

The Nocebo effect/

Maybe worth halving the entry with the negatives of the the nocebo effect included , not just the positive of the placebo effect.
 
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In the latest Skeptic's Dictionary newsletter, Robert Todd Carroll discusses the placebo effect.

In the SD entry, which he has just updated, he expands on this:

The placebo effect is the measurable, observable, or felt improvement in health or behavior not attributable to a medication or invasive treatment that has been administered. [new] The placebo effect is not mind over matter; it is not mind-body medicine. 'The placebo effect' has become a catchall term for a positive change in health not attributable to medication or treatment. As is explained below, the change can be due to many things, such as regression to the mean, spontaneous improvement, reduction of stress, misdiagnosis in the first place, subject expectancy, classical conditioning, etc. [/new]

Most of he highlighted section is wrong. Regression to the mean, misdiagnosis, etc., are not placebo effects. The (US) National Library of Medicine defines placebo effect as follows:

"An effect usually, but not necessarily, beneficial that is attributable to an expectation that the regimen will have an effect, i.e., the effect is due to the power of suggestion."​
 
Sure, psychological changes can effect a myriad of hormones, can effect up or down regulation of the receptors of numerous neurochemicals, alter production rates of endogenous psychoactives, change gene expression via methylation of genes or other reactions like acetylization of their protein sheaths; an entire lexicon of biological changes are psychologically induced.

Any of which, of course, might be contra-indicated if we knew the mechanisms involved in the particular case. Maybe your body's telling you to be depressed and listless because that's the best thing (as determined statistically by evolution) in the given circumstances.

To assume that 'positive' mental processes and the biochemical feedback mechanisms they produce will tend to create an overall 'positive' biochemical change is at the moment pure speculation. Comes down to how you define "positive" and "hopeful" scientifically, in what context and in relation to what.

Value-judgements and science do not mix well :). Just the facts, Ma'am, just the facts.
 
The placebo effect is the measurable, observable, or felt improvement in health or behavior not attributable to a medication or invasive treatment that has been administered. [new] The placebo effect is not mind over matter; it is not mind-body medicine. 'The placebo effect' has become a catchall term for a positive change in health not attributable to medication or treatment. As is explained below, the change can be due to many things, such as regression to the mean, spontaneous improvement, reduction of stress, misdiagnosis in the first place, subject expectancy, classical conditioning, etc. [/new]

Most of he highlighted section is wrong. Regression to the mean, misdiagnosis, etc., are not placebo effects. The (US) National Library of Medicine defines placebo effect as follows:

"An effect usually, but not necessarily, beneficial that is attributable to an expectation that the regimen will have an effect, i.e., the effect is due to the power of suggestion."​

Hi jt512. Yes, that's the correct medical definition.

However, Bob Carroll is explaining the "catchall term", not the medical term:

"The placebo effect is the measurable, observable, or felt improvement in health or behavior not attributable to a medication or invasive treatment that has been administered. [new] The placebo effect is not mind over matter; it is not mind-body medicine. 'The placebo effect' has become a catchall term for a positive change in health not attributable to medication or treatment. As is explained below, the change can be due to many things, such as regression to the mean, spontaneous improvement, reduction of stress, misdiagnosis in the first place, subject expectancy, classical conditioning, etc. [/new]"

Cheers.
 
Here's something I wrote elsewhere:

Sometimes, “placebo effect” is used as shorthand for “any improvement not attributable to an active intervention” – this improvement could be due to a number of factors. When used in this way, the term does cover the true placebo effect, but it also includes the following: "Spontaneous improvement, fluctuation of symptoms, regression to the mean, additional treatment, conditional switching of placebo treatment, scaling bias, irrelevant response variables, answers of politeness, experimental subordination, conditioned answers, neurotic or psychotic misjudgment, psychosomatic phenomena, misquotation, etc." [Kienle and Kiene, 1997]
Also, I found this link interesting: http://www.bmj.com/content/311/7004/551.long (I'm sure I have a copy of the full text but can't find it at the moment.)
 
Here's something I wrote elsewhere:

Sometimes, “placebo effect” is used as shorthand for “any improvement not attributable to an active intervention” – this improvement could be due to a number of factors. When used in this way, the term does cover the true placebo effect, but it also includes the following: "Spontaneous improvement, fluctuation of symptoms, regression to the mean, additional treatment, conditional switching of placebo treatment, scaling bias, irrelevant response variables, answers of politeness, experimental subordination, conditioned answers, neurotic or psychotic misjudgment, psychosomatic phenomena, misquotation, etc." [Kienle and Kiene, 1997]

Also, I found this link interesting: http://www.bmj.com/content/311/7004/551.long (I'm sure I have a copy of the full text but can't find it at the moment.)

Excellent stuff, jdc324! Thank you.
 
Hi jt512. Yes, that's the correct medical definition.

However, Bob Carroll is explaining the "catchall term", not the medical term:

"The placebo effect is the measurable, observable, or felt improvement in health or behavior not attributable to a medication or invasive treatment that has been administered. [new] The placebo effect is not mind over matter; it is not mind-body medicine. 'The placebo effect' has become a catchall term for a positive change in health not attributable to medication or treatment. As is explained below, the change can be due to many things, such as regression to the mean, spontaneous improvement, reduction of stress, misdiagnosis in the first place, subject expectancy, classical conditioning, etc. [/new]"

Cheers.

As the BMJ article linked in an above post states, the phenomena that Carroll lists are not placebo effects, although they are often mistaken for them: "We often and wrongly equate the response seen in the placebo arm of a clinical trial with the placebo effect."

Jay
 
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The term has not become a "catchall term" in any usage I*have ever seen, except on Mr. Carroll's web site.

Quite. A placebo is a simulated therapeutic administered to deceive the recipient into believing it may be efficacious. A placebo effect is the recipient's reported benefit from this treatment.

The placebo effect can only be a catch-all in the sense that it covers any or all of the reported benefits attributed to a placebo.

Otherwise it would be called something else...
 
THE UNCONSCIOUS MIND PLAYS A KEY ROLE IN THE PLACEBO EFFECT

http://myscienceacademy.org/2012/09/11/the-unconscious-mind-plays-a-key-role-in-the-placebo-effect/
With the discovery that the unconscious mind plays a key role in the placebo effect, researchers have identified a novel mechanism that helps explain the power of placebos and nocebos.

Much of medicine is based on what is considered the strongest possible evidence: The placebo-controlled trial. A paper published in the October 19 issue of Annals of Internal Medicine — entitled “What’s In Placebos: Who Knows?” calls into question this foundation upon which much of medicine rests, by showing that there is no standard behind the standard — no standard for the placebo.

Researchers are just starting to appreciate the power that the mind can have over the body, says Tor Wager, an assistant professor of psychology at Columbia University.

“An emerging idea right now is that belief in a placebo taps into processes in your brain that produce physical results that really shape how your body responds to things,” he says. “The brain has much more control over the body than we can voluntarily exert.”

As an example of this, Wager points to the body’s response to perceived threats.

“Say it’s late at night and everything is quiet and then suddenly you see someone outside, near a window,” he explains. “Your body starts to respond. Your pupils dilate. Your heart rate goes up. You start to sweat.”

The belief that something threatening is out there produces a host of physical responses that you have little control over. If you were told to calm down and turn off these sensations, you couldn’t, Wager says. “But if the belief changes — say, it turns out that it’s just your husband coming home — the physical response changes.”

The question, now, is how to tap into these powerful, unconscious responses, Wager says.

The placebo effect is a consciousness event, and more specifically an event in which consciousness and matter interact to change or transform a disease structure into a healing process or flow. At the level of reality at which this event takes place, it is not even possible to say that it is an interaction. This is a level at which consciousness-matter, or as it is more popularly known, mind-body, are not different but are a ‘stuff’, for want of a better word, which is not committed to either condition, yet is both.

It is, in other words, a level of quantum reality. (Quantum reality describes a reality in which something, for example light, can display properties of being both matter and pure energy as waveform.) The laws of quantum mechanics apply rather than the linear-cause effect laws of more conventional science, (including medical science). [....]
 

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