All Placebos Not Created Alike

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All Placebos Not Created Alike

http://www.medicalnewstoday.com/medicalnews.php?newsid=36963

The debate about the existence of a placebo effect has heated up over

the past year as more and more lab experiments are detecting

immediate physiological responses to placebos. A new study takes

placebo investigations out of the lab and into a clinical trial,

showing a discernible placebo effect over time, according to an

article in the Feb. 1 British Medical Journal.

While researchers usually use placebos in clinical trials to test the

effectiveness of a new treatment, this trial pitted one placebo

against another. " It's upside down research, " 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. " We investigated whether a sham acupuncture device has a

greater placebo effect than an inert pill. "

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

versus 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 study 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

Kaptchuk, " 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.

This study takes the first step away from examining the placebo

effect as a generalized phenomenon to one investigating how it varies

in specific clinical environments. Kaptchuk and his colleagues have

initiated other National Institute of Health funded studies that will

explore the placebo phenomenon in clinical trials for different

illnesses and in laboratory experiments that focus on underlying

neurobiological, biochemical, genetic and psychological mechanisms.

Though the results of this study add evidence pointing to the

existence of a placebo effect in a clinical environment, Kaptchuk

does not recommend the use of placebos with patients or deception in

the doctor-patient encounter. The aim is to understand how the ritual

of healing affects health outcomes.

HARVARD MEDICAL SCHOOL

http://hms.harvard.edu/