A new study has pinpointed the unique region in the brain responsible for the placebo effect in pain relief — when a fake treatment actually results in a substantial reduction of pain.
According to researchers from Northwestern Medicine and the Rehabilitation Institute of Chicago (RIC), pinpointing the sweet spot of the pain-killing placebo effect could result in the design of more personalized medicine for the 100 million Americans with chronic pain.
The imaging technology developed for the study has the potential to usher in an era of individualized pain therapy by enabling targeted pain medication based on how an individual’s brain responds to a drug, the researchers explained.
The finding also could lead to more precise and accurate clinical trials for pain medications by eliminating individuals with high placebo response before trials, the researchers noted.
“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 Dr. Marwan Baliki, research scientist at RIC and an assistant professor of physical medicine and rehabilitation at Northwestern University Feinberg School of Medicine.
The scientists discovered a unique brain region within the mid frontal gyrus that identifies placebo pill responders in one trial and was validated 95 percent correct in the placebo group of a second trial.
Using drugs to treat pain has been trial and error, with physicians changing dosage or trying another type of drug if one doesn’t work.
“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,” said Dr. Vania Apkarian, a professor of physiology at Feinberg in whose lab the research was conducted.
“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 — or applied — pain, they translate poorly to the clinic, where pain is mainly chronic, Baliki said.
In the new 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.
They found that taking a placebo pill 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, the researchers noted.
The study was published in PLOS Biology.
Source: Northwestern University