Um... er... discuss.
--David Epstein
[EMAIL PROTECTED]
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http://www.nytimes.com/2001/05/23/health/23CND-PLAC.html
Researchers Debunk Placebo Effect, Saying It's Only a Myth
May 23, 2001
By GINA KOLATA
In a new report that is being met with a mixture of astonishment and,
sometimes, disbelief, two researchers say that the placebo effect is a
myth.
The investigators, Dr. Asbjorn Hrobjartsson and Dr. Peter C. Gotzsche
analyzed 114 published studies involving about 7,500 patients with 40
different conditions. They found no support for the common notion that
about a third of patients will improve if they are given a dummy pill
and told it is real. Their paper appears today in the New England
Journal of Medicine.
[...]
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http://www.nejm.org/content/2001/0344/0021/1630.asp
The New England Journal of Medicine -- May 24, 2001 -- Vol. 344,
No. 21
Editorial: The Powerful Placebo and the Wizard of Oz
Some myths really ought to be true. We react with surprise and
pleasure when we encounter them and then believe them when they neatly
and comfortably help to explain some confusing aspect of our
world. Thereafter, evidence against them is unwelcome and not to be
trusted. But some such myths are flawed and misleading.
[...]
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http://www.nejm.org/content/2001/0344/0021/1594.asp
The New England Journal of Medicine -- May 24, 2001 -- Vol. 344,
No. 21
Is the Placebo Powerless? An Analysis of Clinical Trials Comparing
Placebo with No Treatment
Asbjorn Hrobjartsson, Peter C. Gotzsche
Abstract
Background. Placebo treatments have been reported to help patients
with many diseases, but the quality of the evidence supporting this
finding has not been rigorously evaluated.
Methods. We conducted a systematic review of clinical trials in which
patients were randomly assigned to either placebo or no treatment. A
placebo could be pharmacologic (e.g., a tablet), physical (e.g., a
manipulation), or psychological (e.g., a conversation).
Results. We identified 130 trials that met our inclusion
criteria. After the exclusion of 16 trials without relevant data on
outcomes, there were 32 with binary outcomes (involving 3795 patients,
with a median of 51 patients per trial) and 82 with continuous
outcomes (involving 4730 patients, with a median of 27 patients per
trial). As compared with no treatment, placebo had no significant
effect on binary outcomes, regardless of whether these outcomes were
subjective or objective. For the trials with continuous outcomes,
placebo had a beneficial effect, but the effect decreased with
increasing sample size, indicating a possible bias related to the
effects of small trials. The pooled standardized mean difference was
significant for the trials with subjective outcomes but not for those
with objective outcomes. In 27 trials involving the treatment of pain,
placebo had a beneficial effect, as indicated by a reduction in the
intensity of pain of 6.5 mm on a 100-mm visual-analogue scale.
Conclusions. We found little evidence in general that placebos had
powerful clinical effects. Although placebos had no significant
effects on objective or binary outcomes, they had possible small
benefits in studies with continuous subjective outcomes and for the
treatment of pain. Outside the setting of clinical trials, there is no
justification for the use of placebos. (N Engl J Med
2001;344:1594-602.)
