Placebo

[Graham Lappin]

I have just read a really good account of some studies into the placebo effect. The work was carried out at the Center for Neurobiology of Stress, University of California in Los Angeles (Clin Pharmacol Ther 86(4) 352-354).

The upshot is that they used MRI and PET scans to look at activity in brain in volunteers given a variety of treatments, some of which were placebos. I can't see anything in the article that specifically says these were double blind studies but I suspect they were (the CPT journal is a bit fussy about these sorts of things). There is indeed a cerebral response when placebos are administered and even certain aspects of brain chemistry are affected. For example PET can be used to measure dopamine receptor binding in the brain.

The placebo effect has been known, of course, for a long time but it is interesting to see that some real mechanistic based research is being conducted into the effects.

Now I will play Devil's advocate here and present the following reasoning:

A placebo can be shown to elicit a physiological response
CAMS such as homoeopathy are placebos
Homoeopathy is therefore likely to elicit a physiological response, which shows that it is an active therapy.

Sure, homoeopathy when tested against a placebo fairs no better but that's like testing aspirin against aspirin.

Is there an argument for using the placebo effect as a therapy and if not, why not?

(One more for the road)

[Matt]

Is there an argument for using the placebo effect as a therapy

yes,

the problem is ehtical - informed consent for placebo is tricky although...

[Pebble]

Is there an argument for using the placebo effect as a therapy and if not, why not?

(One more for the road)

One consistent feature of well conducted trials is that the control group do much better than would be predicted from observational data. It matters not whether they receive placebo or not. They live longer, feel better, can exercise more and have fewer symptoms.
While the contributory factors are doubtless complex, being 'cared for' probably plays a substantial role.

The issue then is how to demonstrate that the supposed placebo effects are distinctly different from the sense of well being and subsequent physiological consequences of in effect empathy.

Alt practitioners often cite their 'holistic' approach, which may well simply reflect this aspect. The real question may be how to deliver the needs of individual patients in terms of feeling cared for, as this will vary from patient to patient.

If this construct is correct then placebo or most alt med approaches are like religion, substituting magical thinking for understanding. This ultimately would simply prevent real progress.

[Graham Lappin]

.... If this construct is correct then placebo or most alt med approaches are like religion, substituting magical thinking for understanding. This ultimately would simply prevent real progress.

From the article I read, I am not sure what you are saying here is really correct. The Californian group are reporting measurable mechanistic outcomes from administration of placebos. Surely this is not magical thinking this is good science. Our understanding of the placebo effect in terms of cerebral function and brain chemistry is currently very rudimentary but as this grows, as I am sure it will, is there any reason why the placebo effect cannot become part of mainstream evidenced based medicine?

.... the problem is ehtical - informed consent for placebo is tricky

This is a difficult question but what is and is not ethical is something society decides upon. What was ethical in 1965, might not be viewed in the same way now - and vice versa.

If the placebo effect can alleviate suffering, then is it ethical to withhold its use? Tricky one, I admit.

[Pebble]

From the article I read, I am not sure what you are saying here is really correct. The Californian group are reporting measurable mechanistic outcomes from administration of placebos. Surely this is not magical thinking this is good science. Our understanding of the placebo effect in terms of cerebral function and brain chemistry is currently very rudimentary but as this grows, as I am sure it will, is there any reason why the placebo effect cannot become part of mainstream evidenced based medicine?
.

The question is what efforts were made to ensure that the changes observed with placebo administration could not have been equally induced by a simple reassuring conversation.

[Floppit]

I posted some time ago asking whether the placebo data that builds up over time with well researched diseases is ever meta analysed. I was curious whether it would give insight regarding what areas of clear physical disease show clinical improvement through placebo effect. It wouldn't matter hugely whether the effect was placebo or care and attention as much as it might matter to pull together and make sense of the 'throw away' placebo results that surely must have built up over the years.

Reading the debates in the osteopath thread the extent to which DBRCTs are needed even for very 'measurable' disease (probably wrong word but hope you know what I'm getting at), would suggest the power of psychology over the body is well recognised.

I've probably made a hash of writing that - I'm not with it today!

[Tony Williams]

I find this a fascinating subject, along with its obverse, the nocebo effect (which might more colourfully be called the witchdoctor effect). There are a few documented cases in the west of people who were told they were terminally ill dying as expected despite having nothing physically wrong with them.

There can be no doubt that the mind has a powerful effect on the body and that someone who believes in homeopathy will probably quite genuinely feel better after being treated by a homeopath. I do agree that most of the reason for that is probably the time taken by the homeopaths to talk sympathetically with their patients. There is something soothing about being cared for.

The real danger of placebos like homeopathy is when people think they can cure physical conditions such as diseases. I have the impression that they seem to do fine with the majority of complaints for which there is no verifiable physical cause - e.g. aches, pains and mild depression.

[Graham Lappin]

The question is what efforts were made to ensure that the changes observed with placebo administration could not have been equally induced by a simple reassuring conversation.

The article in CPT was not a full research paper rather than a general review. I really wish I had the time to go through the literature on this but I have pressures of work elsewhere. I certainly accept the question however, and for now all I can say is that the group reporting on the work and the journal are very much world class.

I posted some time ago asking whether the placebo data that builds up over time with well researched diseases is ever meta analysed.

Not my area and so I don't know. It's about 3 am where I am and so I am going to admit I am too lazy to go back through the posts to see if you got an answer. Nevertheless, there are clinical trials with a clinical outcome (however it is measured) and then there are mechanistic studies. The latter is more in my line. For example, a pharmacokinetic study measures the amount of drug in the body over time. This is a parameter independent of anything the subject might tell you and these types of studies are run without placebo or control groups. I am a little bias I know, but it's mechanistic studies that tend to get my attention. The placebo study I mentioned above is a mechanistic study that measured changes in the brain with PET and MRI. Pebbles point still stands in that the study has to be controlled as not to confuse cause and effect, but the outcome is at least a measure other than asking "do you feel better".

The real danger of placebos like homeopathy is when people think they can cure physical conditions such as diseases. I have the impression that they seem to do fine with the majority of complaints for which there is no verifiable physical cause - e.g. aches, pains and mild depression.

Even so, if placebos can genuinely alleviate suffering I don't think their use can be dismissed too easily.

I hope I am not being misunderstood here. I am not for a moment trying to defend the snake oil merchants. My intentions are really about the science of the placebo effect which is difficult to study admittedly. There is a danger that some self deluded nutter tries to cure cancer with placebo (happens all the time). I would argue however that the placebo is like any other therapy, it has to be used in the right way. You could cure something like AIDS with a placebo, but then again if a doctor prescribed aspirin as an AIDS remedy, this would be equally as inappropriate.

Back to get some sleep I think!

[Tony Williams]

You could cure something like AIDS with a placebo, but then again if a doctor prescribed aspirin as an AIDS remedy, this would be equally as inappropriate.

Did you mean to post that or did tiredness cause you to miss out a "not"?

[special_k]

One consistent feature of well conducted trials is that the control group do much better than would be predicted from observational data.

There is another aspect to this, which is that observational data tend to include any and all subjects, whereas in trials a selection process for subjects changes the profile. Somebody might be too sick, or too 'different' for some reason to take part in a trial, but have an experience that's relevant in a clinical setting nevertheless.