We’ve all heard of the “placebo effect,” but until now scientists had no idea where in the brain changes were occurring that result in people taking placebos experiencing reduced pain.
New research from Northwestern Medicine and the Rehabilitation Institute of Chicago (RIC) has pinpointed the “sweet spot” of the pain-killing placebo effect that scientists say, “Could result in the design of more personalized medicine for the 100 million Americans with chronic pain.”
The fMRI technology that was developed for the study has the potential to turning into individualized pain therapy based on an individual’s brain response to a drug.
So, where in the brain is this placebo effect happening?
The scientists discovered a unique brain region within the mid frontal gyrus that identifies placebo pill responders in one trial and can be validated (95 percent correct) in the placebo group of a second trial.
“Given the enormous societal toll of chronic pain, being able to predict placebo responders in a chronic pain population could both help the design of personalized medicine and enhance the success of clinical trials,” said Marwan Baliki, research scientist at RIC and an assistant professor of physical medicine and rehabilitation at Northwestern University Feinberg School of Medicine.
“The new technology will allow physicians to see what part of the brain is activated during an individual’s pain and choose the specific drug to target this spot,” Apkarian said. “It also will provide more evidence-based measurements. Physicians will be able to measure how the patient’s pain region is affected by the drug.”
“Currently, placebo response is primarily studied in healthy subjects within controlled experimental settings. While such experiments aid understanding of the biological and behavioral underpinning of placebo response in experimental (applied) pain, they translate poorly to the clinic, where pain is mainly chronic in nature,” Baliki said.
In this study, scientists used functional magnetic resonance imaging (fMRI) combined with a standard clinical trial design to derive an unbiased brain-based neurological marker to predict analgesia associated with placebo treatment in patients with chronic knee osteoarthritis pain. Scientists showed placebo pill ingestion is associated with a strong analgesia effect, with more than half of the patients reporting significant pain relief.
“If future similar studies can further expand and eventually provide a brain-based predictive best-therapy option for individual patients, it would dramatically decrease unnecessary exposure of patients to ineffective therapies and decrease the duration and magnitude of pain suffering and opioid use,” Baliki and Apkarian said.