Placebo versus placebo

A while ago I posted on a study that showed no difference in outcome between traditional Chinese acupuncture and sham acupuncture. Both interventions were a positive addition to physiotherapy and anti-inflammatory drugs.

Now, a study of sham acupuncture in adults with arm pain shows no difference compared to placebo tablets — neither worked.

But that’s just phase 1 of the study. Now it gets interesting.

In the second phase, the same patients were randomized again. Half entered a sham versus real acupuncture trial. The other half were treated with placebo or a real pain pill. Patients receiving sham acupuncture reported a significant decrease in pain and symptom severity compared to those taking placebo pills. But these are subjective measures of response.

More objective measures of grip strength showed no difference in improvement between the two “placebos.”

Sometimes the ritual associated with the treatment makes its own contribution to the outcome. This is most noticeable when outcomes are measured using subjective parameters. It’s more difficult for the ritual to influence objective outcomes.

For future reference, the sham acupuncture device looks exactly like a real acupuncture needle. When the needle is ?inserted into the skin? participants think they see and feel needle penetration, but the needle has a blunt tip and retracts into a hollow shaft handle.

This study was supported by grant from the National Center for Complementary and Alternative Medicine (NCCAM).

8/5/06 20:00 JR