August 30, 2005


Science plumbs placebo effect (Robert C. Cowen, 8/31/05, CS Monitor)

When an inert placebo acts like a drug, is it just a psychological illusion? Or is it a real biological effect? Research reported last week suggests that it's both. The mere belief that they had received a pain killer was enough to release the brain's natural painkilling endorphins in the patients tested, scientists say.

This opens a new line of research into the placebo puzzle. The effect has been demonstrated often enough to show that some patients appear to benefit from such belief. But there hasn't been enough evidence to convince skeptics that anything more than the so-called power of suggestion is at work. That's changing. "The findings of this study are counter to the common thought that the placebo effect is purely psychological due to suggestion and that it does not represent a real physical change." says University of Michigan neuroscientist Jon-Kar Zubieta. He is principal author of the study published Aug. 24 in The Journal of Neuroscience.

Some mind/body effects are well known. Adrenaline flows when firefighters go into action. The sight of a lion induces physical changes that prepare a zebra to flee. Humans often experience a similar fight-or-flight reaction to a perceived threat.

But it's been too much of a stretch for many neuroscientists to accept that belief in fake medication can produce medical benefits that can be objectively verified.

Mere belief?

Posted by Orrin Judd at August 30, 2005 8:45 PM

Yup. Mere belief. Free will. Kind of like how people believe lots of other things that really aren't there.

Posted by: Reiko at August 31, 2005 8:51 AM

Except, as the study suggests, they are there.

Posted by: oj at August 31, 2005 8:59 AM

This study is ridiculous. Do you think that God comes down says, "Well, since you believe that your doing cocaine or heroin, even though you aren't, I guess that I'll affect your physical and chemical neurology so that it seems like you are."

Posted by: Reiko at August 31, 2005 9:14 AM


Yes. Religious experience is not dissimilar to the effects of drugs. Those who can't order themselves internally seek solace in drugs.

Posted by: oj at August 31, 2005 9:20 AM

Wasn't ther a study a few years by a Danish medical team (published in the Lancet IIRC) that showed that the "placebo effect" simply did not exist? Apparently, the recorded effectiveness of any placebo is merely a statistical regression to the mean.

Posted by: Anon at August 31, 2005 11:48 AM

I found this follow up to current research on the "placebo effect" (including the Danish study) at

Unfortunately, not all evidence supports the existence of a placebo effect. The strongest scientific criticism against it was published in 2001, when a Danish study reviewed 114 previous studies that compared the effectiveness of real treatments to both placebos and no treatment at all. It found that the placebo effect was either nonexistent or wildly overblown. A little skepticism was actually long overdue. The original basis for the placebo effect was a 1955 paper by an anesthesiologist that claimed, without much substantiation, that 35 percent of patients got better with a dummy pill. The number entered medical folklore without further scrutiny.

On the other hand, the Danish study was not as powerful as it seemed at first. It was not an independent test of the placebo effect versus no treatment, but a review of other studies. Remember, the absence of evidence does not equal evidence of absence. It may mean there was no effect, or it may signal only that effects weren't detected.

Further, the definition of a placebo used in this analysis was broad. It included a psychiatric study of "nondirectional neutral conversations," (or, in English, vague chats) as opposed to talk therapy. Should informal conversations with a doctor, no matter how reassuring, fit the definition of a placebo trial? Given that placebo advocates note greater effectiveness depending on the type of placebo - those given by injection are more effective than drinking colored liquid, while people given a placebo said to be morphine report less pain than patients told they were receiving generic aspirin - counting nebulous conversations as placebos probably understates the impact.

The two more recent studies provide powerful evidence that the placebo effect is noisily alive. Perhaps the most convincing evidence for its existence was revealed in February, when Science magazine announced that Swedish and Finnish researchers had shown that placebos activate the same brain circuits as painkilling drugs. It may be that the placebo response is actually part of all painkilling treatments. These studies show that we dismiss the power of the placebo at our peril.

Posted by: Anon at August 31, 2005 11:55 AM

Obviously people have forgotten the epidemic in illegal placebo use during the '70s. It suddenly evaporated when people realized that their stupid behavior (like wearing ugly polyester and going to discos) wasn't chemically induced, but their own fault.

Posted by: Raoul Ortega at August 31, 2005 2:40 PM