Specifying the non-specific components of acupuncture analgesia.

It is well known that acupuncture has pain-relieving effects, but the contribution of specific and especially non-specific factors to acupuncture analgesia is less clear. One hundred and one patients who developed pain ⩾ 3 on a visual analog scale (VAS, 0-10) following third molar surgery were randomized to receive active acupuncture, placebo acupuncture, or no treatment for 30 min with acupuncture needles with potential for double-blinding. Patients' perception of the treatment (active or placebo) and expected pain levels (VAS) were assessed prior to and halfway through the treatment. Looking at actual treatment allocation, there was no specific effect of active acupuncture (P = 0.240), but a large and significant non-specific effect of placebo acupuncture (P < 0.001), which increased over time. Interestingly, however, looking at perceived treatment allocation, there was a significant effect of acupuncture (P < 0.001) indicating that patients who believed they received active acupuncture had significantly lower pain levels than those who believed they received placebo acupuncture. Expected pain levels accounted for significant and progressively larger amounts of the variance in pain ratings following both active and placebo acupuncture (up to 69.8%). This is the first study to show that under optimized blinding conditions non-specific factors such as patients' perception of and expectations toward treatment are central to the efficacy of acupuncture analgesia and that these factors may contribute to self-reinforcing effects in acupuncture treatment. To obtain an effect of acupuncture in clinical practice it may, therefore, be important to incorporate and optimize these factors.
Copyright © 2013. Published by Elsevier B.V.
PMID: 23707680