Medical evidence is based on what is considered the strongest possible foundation, the placebo-controlled trial but a new paper in the Annals of Internal Medicine calls into question this foundation upon which much of medicine rests, by showing that there is no standard behind the standard – that is, there is no standard for the placebo.
The thinking behind relying on placebo-controlled trials is that to be sure a treatment is effective, it needs to compare people whose only difference is whether or not they are taking the drug. Both groups must think they are on the drug to protect against effects of factors like expectation. Study participants are allocated "randomly" to the drug or a "placebo" – a pill that might be mistaken for the active drug but is inert.
But, according to the paper's author, Beatrice Golomb, MD, PhD, associate professor of medicine at the University of California, San Diego School of Medicine, this standard has a fundamental problem, "there isn't anything actually known to be physiologically inert. On top of that, there are no regulations about what goes into placebos, and what is in them is often determined by the makers of the drug being studied, who have a vested interest in the outcome. And there has been no expectation that placebos' composition be disclosed. At least then readers of the study might make up their own mind about whether the ingredients in the placebo might affect the interpretation of the study."
Golomb pointed out these limitations to the placebo in a pair of letters to the journal Nature 15 years ago:
"A positive or negative effect of the placebo can lead to the misleading appearance of a negative or positive effect of the drug," she said. "And an effect in the same direction as the drug can lead a true effect of the drug to be lost. These concerns aren't just theoretical. Where the composition has been disclosed, the ingredients of the placebo have in some instances had a likely impact on the result of the study – in either direction (obscuring a real effect, or creating a spurious one). In the cases we know about, this is not because of any willful manipulation, but because it can in fact be difficult to come up with a placebo that does not have some kind of problem."
Since 15 years have elapsed, the situation might have improved, so Golomb and her colleagues analyzed just how often randomized trials published in the past two years in each of the top four general medical journals actually disclosed the makeup of placebos.
The answer was not reassuring, according to the researchers, who found that the placebo ingredients for pills were disclosed in fewer than 10 percent of cases. The nature of the "control" was significantly more likely to be stated for other types of treatments, like injections, acupuncture, or surgery, where people are more likely to question what 'placebo' actually means in that context.
"How often study results are affected by what's in the placebo is hard to say – because, as this study showed, most of the time we have no idea what the placebo is," Golomb concluded.
Citation: Beatrice A. Golomb, Laura C. Erickson, Sabrina Koperski, Deanna Sack, Murray Enkin, Jeremy Howick, 'What's in Placebos: Who Knows? Analysis of Randomized, Controlled Trials', Ann Intern Med October 19, 2010 153:532-535
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Erupting Bardarbunga Volcano In Iceland Sits On A Massive Magma Hot Spot
- Researchers Created A Laser Bullet To See What It Would Look Like - And Here It Is
- Genetically Modified Stem Cells Kill Brain Tumors
- How Gut Bacteria Ensure A Healthy Brain – and Could Play A Role In Treating Depression
- Ebola's Evolutionary Roots Are Ancient
- We're Too Late To Prevent 137,000 More Ebola Cases, Says Epidemiology Paper
- Home, Workplace, Tomb – Fury And The Reality Of The World War II Tank
- "/* Science advances as much by mistakes as by plans. */ Apparently the mainstream physicists are..."
- "Part of being a theorist in any subfield is trying to explain the results that we have in hand..."
- "This essay interested me immensely. My father claimed to be an 'atheist' all his life but..."
- "Not all of us are explorers, much less pioneers. The author is certainly not the latter and too..."
- " Obviously 300% more fish farming means more illnesses and more antibiotic use.Is it really..."
- How to sell a toxic pesticide the smart way–call it organic
- Leftist dystopia? Anti-technology fever animates opposition to GMOs and other ‘disruptive’ technologies
- CDC faced a nearly impossible balancing act with Ebola, and failed
- Why Chobani reversed course, making yoghurt only from milk from cows not fed GMO grain
- Monterey, California, hotbed of anti-GMO activism, home to new GMO corn farm
- Evolution is sometimes messy or even outright ridiculous
Books By Writers Here