Study Highlights Battle of the Placebos
The debate about the existence of
a placebo effect has heated up over the past year as a growing number
of lab experiments are detecting immediate physiological responses
to placebos. In terms of hands-on research, placebos often taken
the form of fake, or sham, treatments. Sham massage, for example,
may consist of the application of lotion to a client without the
use of traditional massage strokes.
A new study by researchers at Harvard
University takes placebo investigations out of the lab and into
a clinical trial, showing a discernible placebo effect over time.
While researchers usually use placebos
in clinical trials to test the effectiveness of a new treatment,
this trial pitted two placebos—a sham acupuncture device and
an inert pill—against each other, according to a university
The study of 270 individuals with
chronic arm pain had two phases. In the first phase, 135 patients
were given sham acupuncture, and another 135 patients were given
a placebo pill for two weeks. During this period, investigators
found no strong evidence for an enhanced effect with placebo devices
compared with placebo pills.
In the second phase of the study,
the same patients were randomized again, with half the patients
entered in a sham acupuncture device vs. real acupuncture trial,
and the other half in a placebo pill vs. real pain-pill trial. The
acupuncture trial extended four more weeks (the length believed
needed to see improvement), and the pill trial lasted six more weeks
(the length needed to have the real drug in the bloodstream).
In the second phase of the study,
patients receiving sham acupuncture reported a more significant
decrease in pain and symptom severity than those receiving placebo
pills for the duration of the trials. The results of this phase
show that the placebo effect varies by type of placebo used.
“These findings suggest that
the medical ritual of a device can deliver an enhanced placebo effect
beyond that of a placebo pill. There are many conditions in which
ritual is irrelevant when compared with drugs, such as in treatment
of a bacterial infection,” said Ted Kaptchuk, assistant professor
of medicine and associate director of the Division for Research
and Education in Complementary and Integrative Medical Therapies
and the Osher Institute at Harvard Medical School, “but the
other extreme may also be true. In some cases, the ritual may be
the critical component.”
The enhanced placebo effect illustrated
in this study applied only to subjective reports from patients about
their perception of pain and the severity of their condition. More
objective measures of grip strength showed no difference in improvements
between the two placebos.
The results also provided evidence
that what doctors tell patients about side effects directly influences
their experience of them. Prior to participating in the study, doctors
provided informed consent forms alerting the patients as to the
side effects they might experience: temporary soreness for acupuncture
and fatigue and dry-mouth for the pills. Of those receiving placebos,
25 percent of sham acupuncture and 31 percent of placebo pill patients
reported experiencing the very side effects suggested to them even
when nothing was administered to cause them.
Results of the study were summarized
in the Feb. 1 issue of the British Medical Journal.