The Placebo Effect Strikes Again
Every once in a while a clinical trial produces results that are difficult to accept. Such is the case with a study involving hotel maids published in the journal Psychological Science last year (February 2007, Vol 18, Issue 2). A recent segment of Morning Edition on National Public Radio brought the study to my attention.
The researchers began by measuring the maids’ weight, blood pressure, and body mass index, among other things. And they were all asked about their exercise habits. Interestingly, most reported that they exercised little or not at all on a daily basis. At this point, the maids were divided into two groups. One group was shown how the work they did daily as maids was, in fact, exercise and were told how many calories each of their daily routine cleaning activities burned. The other group (the “control” group) was not given this exercise and calorie information. But they were all observed for 4 weeks, at which time their weights, blood pressures and body mass indexes were measured again and they were again asked about their exercise habits.
What the researchers found was that the group given the exercise and calorie information actually lost weight and registered lowered blood pressure and body mass index, while the control group did not experience these changes. Because they were all observed, the researchers made sure that neither group was actually changing their daily routine.
What could possibly explain this observation?
In January of 2006, I blogged a couple of times on a phenomenon known popularly as "the placebo effect." The experiment with the hotel maids seems to provide evidence of a specific and rather amazing (to most people, at least) placebo effect. The fact that the one group of maids knew they were exercising somehow caused them to lose weight although they apparently did nothing extraordinary to change what they did or ate. The knowledge alone seems to have effected the change.
This study is not without its detractors. Even its authors agree more research is needed to answer lingering questions. But it does provide an example of how some clinical studies can lead to results that capture the imagination - of scientists and the rest of us.
By the way, the American Medical Association's policy on placebo use stipulates that their use by physicians is acceptable only when patients are informed of their use and agree to it.
It wouldn't be surprising to see further developments in this area of research and medicine over the next few years.
-Joe
Related Topics:
The researchers began by measuring the maids’ weight, blood pressure, and body mass index, among other things. And they were all asked about their exercise habits. Interestingly, most reported that they exercised little or not at all on a daily basis. At this point, the maids were divided into two groups. One group was shown how the work they did daily as maids was, in fact, exercise and were told how many calories each of their daily routine cleaning activities burned. The other group (the “control” group) was not given this exercise and calorie information. But they were all observed for 4 weeks, at which time their weights, blood pressures and body mass indexes were measured again and they were again asked about their exercise habits.
What the researchers found was that the group given the exercise and calorie information actually lost weight and registered lowered blood pressure and body mass index, while the control group did not experience these changes. Because they were all observed, the researchers made sure that neither group was actually changing their daily routine.
What could possibly explain this observation?
In January of 2006, I blogged a couple of times on a phenomenon known popularly as "the placebo effect." The experiment with the hotel maids seems to provide evidence of a specific and rather amazing (to most people, at least) placebo effect. The fact that the one group of maids knew they were exercising somehow caused them to lose weight although they apparently did nothing extraordinary to change what they did or ate. The knowledge alone seems to have effected the change.
This study is not without its detractors. Even its authors agree more research is needed to answer lingering questions. But it does provide an example of how some clinical studies can lead to results that capture the imagination - of scientists and the rest of us.
By the way, the American Medical Association's policy on placebo use stipulates that their use by physicians is acceptable only when patients are informed of their use and agree to it.
It wouldn't be surprising to see further developments in this area of research and medicine over the next few years.
-Joe
Related Topics:
- WebMD Video: How Do Placebos Work?
- The Placebo Effect
- Lessons From the Placebo Effect: A New Design for Clinical Trials?
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