Researchers at Northwestern University have shown that sugar pill placebos are as effective as any drug on the market for relieving chronic pain in people with a certain brain anatomy and psychological characteristics. Amazingly, such patients will even experience the same reduction in pain when they are told the pill they are taking has no physiological effect.

Previous studies have found that placebos can have an effect on a number of conditions, including sleep disorders, depression and pain. The new Northwestern study, however, has shown it is possible to predict which patients suffering from chronic pain will experience relief when given a sugar pill – and it's basically all in their heads.

"Their brain is already tuned to respond," says senior study author A. Vania Apkarian, professor of physiology at Northwestern University Feinberg School of Medicine. "They have the appropriate psychology and biology that puts them in a cognitive state that as soon as you say, 'this may make your pain better,' their pain gets better."

Additionally, there's no need for subterfuge because those primed to respond to a placebo will do so even when they know that's what they're getting.

"You can tell them, 'I'm giving you a drug that has no physiological effect but your brain will respond to it,'" Apkarian adds. "You don't need to hide it. There is a biology behind the placebo response."

The study involved 60 patients experiencing chronic back pain who were randomly split into two arms. Subjects in one arm were given either a real pain relief drug or a placebo – those receiving the drug weren't studied by the researchers. Those in the other arm received neither the drug or a placebo and served as the control group.

Patients that received the placebo and reported a reduction in pain were examined and found to have a similar brain anatomy and psychological traits, such as the right side of their emotional brain being larger than the left and a larger cortical sensory area than those in the placebo group that reported no reduction in pain. The researchers say the patients that had a response to the placebo were also more emotionally self-aware, sensitive to painful situations, and mindful of their environment.

The researchers say their findings have a number of potential benefits, the most obvious being the ability for doctors to prescribe a placebo rather than addictive pharmacological drugs that may have negative long-term effects, while getting the same result. Prescribing a cheap sugar pill would also result in a significant reduction in healthcare costs for the patient and the health care system as a whole.

"Clinicians who are treating chronic pain patients should seriously consider that some will get as good a response to a sugar pill as any other drug," says Apkarian. "They should use it and see the outcome. This opens up a whole new field."

Additionally, the findings may make it possible to eliminate the placebo effect from drug trials, meaning fewer subjects would need to be recruited and it would be easier to identify the physiological effects of the drug under examination.

The team's research is published in Nature Communications.