Placebo responses to medical device therapy for pain

Placebo response to a functionless machine was tested in 58 patients with chronic pain. Thirteen discontinued treatment before the planned trials were complete: 5 did so because sham therapy worsened their pain. Forty-five patients completed three trials of treatment with a magnetic device, one trial of which was a sham. Thirteen percent of patients undergoing sham therapy experienced relief of pain, improved range of motion, and decrease in muscle spasm. Eleven percent of the sham trials resulted in significant increase in pain. The placebo/nocebo response to sham therapy with a device is similar to that previously reported for prolonged drug treatment, but is lower than the placebo rate for short-term medication trials.