Research conducted at Northwestern Medicine and the Rehabilitation Institute of Chicago (RIC) has identified the region in the brain responsible for the “placebo effect” in pain relief for the first time. The placebo effect is when a fake treatment actually results in considerable decrease of pain.
The 100 million Americans with chronic pain could find relief through the design of more personalized medicine because of the identification of the sweet spot of the pain killing placebo effect. The fMRI technology developed for the study could possibly usher in an era of individualized pain therapy. Targeted pain drugs based on how an individual’s brain responds to a medication might be developed to achieve this.
Eliminating individuals with a high placebo response before clinical trials for pain medications will result in the trials being more accurate and precise.
In one trial, a unique brain region within the mid frontal gyrus was discovered. This region detects placebo pill responders. In a second trial, the results of the first trial was validated with a 95 percent accuracy in the placebo group.
Marwan Baliki, a research scientist at RIC and an assistant professor of physical medicine and rehabilitation at Northwestern University Feinberg School of Medicine, and Vania Apkarian, professor of physiology at Feinberg, are both corresponding authors on the paper. The research was done at Apkarian’s lab.
Baliki notes that being able to predict placebo responders in a chronic pain population can enhance the success of clinical trials and help in the design of personalized medicine. This would greatly reduce the huge societal toll of chronic pain.
Physicians use trial and error to treat patients’ pain. If one drug doesn’t work, they either switch to another or change the dosage.
Apkarian explains that doctors will be able to use the new technology to see what part of the brain is activated during an individual’s pain. This will help them select the specific drug that targets this spot. Doctors will also be able to measure how the patient’s pain region is affected by the drug, thus obtaining evidence based feedback on the effectiveness of the treatment.
Baliki adds that current placebo response studies is done with healthy subjects within controlled investigational settings. Although these experiments improve the understanding of the behavioral and biological underpinning of placebo response in applied pain, they don’t help much in the clinic where pain is mostly chronic in nature.
Functional magnetic resonance imaging (fMRI) was combined with a standard clinical trial design for this study. The focus was on developing an unbiased brain based neurological marker to forecast analgesia related with placebo treatment in patients with chronic knee osteoarthritis pain. More than half of the patients reported significant pain relief and the researchers feel they have demonstrated that ingesting a placebo pill is linked to a strong analgesia effect.
Baliki and Apkarian are both of the opinion that the duration and magnitude of pain suffering and opioid use, and unnecessary exposure of patients to ineffective therapies can be decreased in the future. This would however require similar studies that expand on their results and eventually provide a brain based predictive therapy option for individual patients.
The full study was published in the journal PLOS Biology.
