Placebo response varies between different types of sham acupuncture
Placebo responses to sham controls used in experimental studies of neck pain differ significantly depending on the type of sham procedure employed, and also depend on the outcome measure used. Chinese investigators randomly assigned 175 patients with neck pain to receive 10 sessions of either electro-acupuncture, shallow acupuncture, non-acupoint deep acupuncture, non-acupoint shallow acupuncture, or non-penetrating acupuncture. They used the Northwick Park Neck Pain Questionnaire (NPQ) as their primary outcome measure, and the Short-form McGill Pain Questionnaire, visual analog scale (VAS), and Pain Threshold as secondary outcomes to measure the changes from baseline to a three-month follow up. All groups except non-acupoint shallow acupuncture showed significant improvements in all outcome measurements. Electro-acupuncture only showed improvements that were superior to shallow acupuncture, non-acupoint shallow acupuncture and non-penetration groups when compared using the NPQ and VAS scales. Interestingly, the non-acupoint shallow acupuncture procedure produced even less placebo response than non-penetrating acupuncture.