Placebos and the Placebo Effect

[Nanfeishen]

So we read many medical trials about one group being given placebos and the other the "drug", but what precisely is in the actual placebo?

It seems that most of the time, the ingredients of the placebo is often ignored or remains undisclosed in the final report of the study.

2 interesting little articles on the subject:

How do we know the placebo did not have an effect if we don't know what the placebo was?

Indeed, the researchers highlight two cases in which ingredients were revealed and may have affected the study. In one older study of heart disease, control group patients were given placebos of corn oil or olive oil. We now know both can lower cholesterol levels. Another earlier study of cancer and HIV patients dispensed lactose sugar placebos, a problem when patients suffering from those diseases often suffer an increased risk of lactose intolerance.

http://news.discovery.com/human/whats-in-a-placebo-turns-out-we-dont-really-know.html

Study Selection: 3 reviewers screened titles and abstracts of the journals to identify randomized, placebo-controlled trials published from January 2008 to December 2009.

Data Synthesis: Most studies did not disclose the composition of the study placebo. Disclosure was less common for pills than for injections and other treatments (8.2% vs. 26.7%; P = 0.002).

Conclusion: Placebos were seldom described in randomized, controlled trials of pills or capsules. Because the nature of the placebo can influence trial outcomes, placebo formulation should be disclosed in reports of placebo-controlled trials.

http://www.annals.org/content/153/8/532.abstract

If this is the case, then how accurate can one say many of these trials actually are ?

 

[Geriatrix]

Interesting post Nanfeishen.
I recall reading news a while back where they discussed the fact that placebos seem to be getting more effective than than they used to be and that this make viable studies difficult.