Placebo Effect - No proof that it exists

[dipic]

http: // www . prohealth . com /me-cfs/blog/boardDetail . cfm?id=1363626

(take out the spaces, obviously)

What does everyone think of this?

 

[Puppycow]

Hint: There's a reason why noobs are prohibited from posting links. It's to prevent this kind of spamming. Please start a discussion by stating your position or question, not a link.

As far as the placebo effect is concerned, it is a well-known and well-documented phenomenon.

http://en.wikipedia.org/wiki/Placebo_effect#Placebo_effect

 

[dipic]

Sorry but I'm not spamming. Perhaps I should have cut and pasted or summarized the contents of the link but I wanted to leave the original source.

If you went to the link you would know that the poster links to a pubmed article that challenges the placebo effect:

In 1955, Henry K. Beecher published the classic work entitled "The Powerful Placebo." Since that time, 40 years ago, the placebo effect has been considered a scientific fact. Beecher was the first scientist to quantify the placebo effect. He claimed that in 15 trials with different diseases, 35% of 1082 patients were satisfactorily relieved by a placebo alone. This publication is still the most frequently cited placebo reference. Recently Beecher's article was reanalyzed with surprising results: In contrast to his claim, no evidence was found of any placebo effect in any of the studies cited by him. There were many other factors that could account for the reported improvements in patients in these trials, but most likely there was no placebo effect whatsoever. False impressions of placebo effects can be produced in various ways. 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. These factors are still prevalent in modern placebo literature. The placebo topic seems to invite sloppy methodological thinking. Therefore awareness of Beecher's mistakes and misinterpretations is essential for an appropriate interpretation of current placebo literature.

My question was what do others think about this, as I've always believed that placebo was a scientifically proven phenomena. I also obviously disagree with the poster's notion that "Big Pharma reps and their salesmen (doctors) love to use placebo propaganda to keep people buying their drugs instead of natural herbs and other alternative treatments. Yet, there is no proof that a placebo effect even exists."

I apologize for not stating so in my original post.

 

[Cavemonster]

Sorry but I'm not spamming. Perhaps I should have cut and pasted or summarized the contents of the link but I wanted to leave the original source.

If you went to the link you would know that the poster links to a pubmed article that challenges the placebo effect:




My question was what do others think about this, as I've always believed that placebo was obviously a scientifically proven phenomena.

I apologize for not stating so in my original post.

There's no information about the actual process they used to review the original studies. The language of the abstract isn't really the way studies are presented, and it isn't clear where this was published.

In the 54 years since Beecher, many many studies have confirmed placebo effects again and again. Analysis of his work is to the placebo effect what analysis of Darwin's handwriting is to evolution.

 

[sol invictus]

Why is this hard to test?

Take a group of sick people. Divide randomly into thirds. To one group, give a real medicine. To the second, an inert pill. To the third, nothing. Evaluate the results.

If group 2 did better than 3 (2>3), the placebo effect exists. If 1>2, the medicine works. If 2>3>1, either the medicine is harmful or the experiment was bad.

Such experiments are done constantly, aren't they?

 

[MattusMaximus]

FAIL

 

[fls]

http://www.prohealth.com/me-cfs/blog/boardDetail.cfm?id=1363626

Yeah, there isn't really much of a placebo effect. Studies done comparing placebo to no treatment don't show a difference on binary outcomes (pain present or absent, nausea present or absent). And they don't show a difference on continuous variables except those which are subjective and prone to reporting bias anyway. Even pain relief doesn't reach a clinically significant level (although the difference is statistically significant). It's kinda disheartening.

http://content.nejm.org/cgi/content/abstract/344/21/1594

However, this info is particularly destructive for alternative medicine, since the reason it appears to have an effect is due to those biases which create the placebo effect. At least evidence-based medicine has the benefit of showing effect beyond placebo.

Linda

 

[The Atheist]

Hint: There's a reason why noobs are prohibited from posting links. It's to prevent this kind of spamming. Please start a discussion by stating your position or question, not a link.

What is this crud?

There is no obligation on anyone to state a position, nor is one link spamming.

 

[Puppycow]

I think we need a strict definition of the term "placebo effect" before we can determine whether it exists or not.
From the Wikipedia article in post #2:

A placebo is a sham medical intervention. In one common placebo procedure, a patient is given an inert sugar pill, told that it may improve his/her condition, but not told that it is in fact inert. Such an intervention may cause the patient to believe the treatment will change his/her condition; and this belief does indeed sometimes have a therapeutic effect, causing the patient's condition to improve. This phenomenon is known as the placebo effect.

So if it is defined as "a therapeutic effect, causing the patient's condition to improve," rather than simply "an effect causing the patient to report an improvement," (or some similar lower hurdle) perhaps it does not exist? I think there's little doubt that there is "an effect causing the patient to report an improvement," but I don't know if there is "a therapeutic effect, (actually) causing the patient's condition to (actually) improve." For one thing, we know that correlation does not necessarily mean causation.

Does everyone agree that the correct definition of "placebo effect" is "a therapeutic effect, (actually) causing the patient's condition to (actually) improve"?

 

[Prometheus]

Skepdic has a good article on Placebo.

A lot of people mistakenly think of placebo as some kind of Mind Over Matter phenomenon rather than just a statistical conflation of all sorts of things like confirmation bias, poor study design, uncontrolled variables, regression to mean, and just plain chance.

 

[Puppycow]

What is this crud?

There is no obligation on anyone to state a position, nor is one link spamming.

I like my links clickable.

And noobs must be hazed.

 

[Cavemonster]

Does everyone agree that the correct definition of "placebo effect" is "a therapeutic effect, (actually) causing the patient's condition to (actually) improve"?

No, I can't agree to that definition. The reason for placebo trials includes instances where reporting of improvement can't be easily differentiated from improvement, and some reporting of side effects can't be differentiated from real side effects.

The practical reason for using placebos in trials are the real placebo effect.

 

[sol invictus]

Skepdic has a good article on Placebo.

A lot of people mistakenly think of placebo as some kind of Mind Over Matter phenomenon rather than just a statistical conflation of all sorts of things like confirmation bias, poor study design, uncontrolled variables, regression to mean, and just plain chance.

That's not what your link says. For example:

Thoracotomized patients were treated with buprenorphine [a powerful pain reliever] on request for 3 consecutive days, together with a basal intravenous infusion of saline solution. However, the symbolic meaning of this basal infusion was changed in three different groups of patients. The first group was told nothing about any analgesic effect (natural history). The second group was told that the basal infusion was either a powerful painkiller or a placebo (classic double-blind administration). The third group was told that the basal infusion was a potent painkiller (deceptive administration). Therefore, whereas the analgesic treatment was exactly the same in the three groups, the verbal instructions about the basal infusion differed. The placebo effect of the saline basal infusion was measured by recording the doses of buprenorphine requested over the three-days treatment. We found that the double-blind group showed a reduction of buprenorphine requests compared to the natural history group. However, this reduction was even larger in the deceptive administration group. Overall, after 3 days of placebo infusion, the first group received 11.55 mg of buprenorphine, the second group 9.15 mg, and the third group 7.65 mg. Despite these dose differences, analgesia was the same in the three groups. These results indicate that different verbal instructions about certain and uncertain expectations of analgesia produce different placebo analgesic effects, which in turn trigger a dramatic change of behaviour leading to a significant reduction of opioid intake.

The patients who thought their IV contained a powerful pain reliever required 34% less of the analgesic than the patients who weren't told anything about their IV and 16% less than the patients who were told the IV could be either a powerful pain killer or a placebo. Each group got exactly the same amount of pain killer but their requests for the analgesic differed dramatically. The only significant difference among the three groups was the set of verbal instructions about the basal infusion. The study was too short for the differences to be explained by the natural history of recovery, regression, or any of the other alternatives found by Hróbjartsson and Götzsche.

 

[Prometheus]

That's not what your link says. For example:

The study you quote could equally well be interpreted to mean that differing instructions have a different suggestive effect upon patients' behaviour as opposed to on their actual experience of pain. I'd likely lump that one in with either "poor study design" or perhaps "over-stated conclusion".

 

[Puppycow]

No, I can't agree to that definition. The reason for placebo trials includes instances where reporting of improvement can't be easily differentiated from improvement, and some reporting of side effects can't be differentiated from real side effects.

The practical reason for using placebos in trials are the real placebo effect.

So what is your definition of the term?

 

[bpesta22]

Placebo effect seems to be just a catch all description for any improvement seen in the control group before and after.

The cause of it could be error in measurement, regression to the mean, some psychological benefit to thinking one got treated or a demand characteristic. I think specific reasons for why a placebo effect might occur are well known (from hawthorne effects to subjects trying to be good subjects). The problem seems to be lumping all into one thing and calling it a placebo effect?

 

[sol invictus]

The study you quote could equally well be interpreted to mean that differing instructions have a different suggestive effect upon patients' behaviour as opposed to on their actual experience of pain.

What's the difference?

 

[Cavemonster]

So what is your definition of the term?

I'll go with this one.

n

The real or imagined effect of a placebo, which may actually be the same effect ordinarily associated with the administration of a therapeutically active agent.

In terms of issues like pain, there just isn't a good way to separate patient reporting from actual effect. Heck what does it even mean to parse the difference between feeling less pain and thinking that you feel less pain?

 

[Puppycow]

Placebo effect seems to be just a catch all description for any improvement seen in the control group before and after.

The cause of it could be error in measurement, regression to the mean, some psychological benefit to thinking one got treated or a demand characteristic. I think specific reasons for why a placebo effect might occur are well known (from hawthorne effects to subjects trying to be good subjects). The problem seems to be lumping all into one thing and calling it a placebo effect?

So whether it is "proven" to "exist" or not depends on how it is defined. Obviously, "any improvement seen in the control group" exists, but tells us nothing about what caused the improvement.

Likewise:

The real or imagined effect of a placebo, which may actually be the same effect ordinarily associated with the administration of a therapeutically active agent.

This is defined in a way that it essentially can't not exist.

 

[Prometheus]

What's the difference?

If the varying instructions merely cause patients to have an actual improvement in the drug's effect rather than just motivating patients to behave differently (to request more or less drugs regardless of how they actually feel) then we might placebo effects of similar size in studies of conditions where a change in patient behaviour could not be relevant to the measured health effects.

I'm not well-versed enough in the research literature to say whether this is the case or not. I just don't find that particular study to be enough to convince me.