Placebo reduces back pain—even when patients know they're taking placebo

For patients with chronic back pain, "open" treatment with placebo—informing patients that they are taking an inactive pill, and why it might be helpful—leads to reductions in pain and disability, reports a study in Pain, the official publication of the International Association for the Study of Pain (IASP).

"This study is the first to demonstrate potential clinically significant benefits of open placebo treatment in chronic low back pain," according to the new research by Claudia Carvalho, PhD, of ISPA-Instituto Universitário, Lisbon, and colleagues. "Our data suggests that harnessing placebo effects without deception is possible in the context of a plausible rationale."

Better Improvement When Open Placebo Is Added to Pain Medications

The study included 97 adult patients with low back pain lasting at least three months. Patients were randomly assigned to three weeks of treatment on their usual pain medications alone, or on their usual medications plus placebo.

But unlike the usual "placebo-controlled" study, patients knew they were taking a placebo. The researchers explained to patients about the "potentially powerful" placebo effect, and how the body may automatically respond to placebo treatments. Previous studies have suggested that placebos can have "clinically meaningful benefits"—possibly reflecting "non-conscious processes" related to participating in a study and taking pills.

Measures of back pain and disability were compared between groups. After three weeks, patients initially assigned to usual treatment were offered the chance to take placebo pills. Eighty-three patients completed the study.

The results showed greater reductions in pain for patients assigned to placebo. On a 0-to-10 scale, patients in the placebo group had a 1.5-point improvement in pain score, compared to no significant change for patients taking usual medications only. The placebo group also had nearly a three-point reduction in back pain-related disability score, compared to no change for the usual-treatment group.

Overall, open placebo treatment reduced initial pain and disability scores by approximately 30 percent. Patients in the usual-treatment group had similar improvements after they started taking placebo pills. There were no adverse effects in either group.

There's a pressing need for more effective treatments for low back pain, which causes more disability worldwide than any other medical condition. Conventional "double-blind" trials often find commonly prescribed treatments for back pain are no more effective than inactive placebos.

Could the placebo effect be used to improve treatment of back pain? Giving placebo pills in open fashion—including explanations of how the placebo effect may work—offers a way to overcome the ethical conflict of deceiving patients that they are taking an active medication.

The researchers acknowledge some limitations of their study, particularly its small size and short duration. They also note that it was advertised as a "mind-body clinical study," which might have attracted patients who are concerned about conventional medicine or attracted to complementary and alternative treatments.

"Our data suggest that open-label placebo can be a safe and effective adjunct to treatment for chronic low back pain," Dr. Carvalho and coauthors conclude. They call for further studies evaluating the potential for "harnessing placebo effects without deception," for back pain as well as other conditions.