Many chronic pain sufferers resent being told by friends and family that “the pain is all in your head.”
But a new study out of Northwestern University found there is some truth behind that cliché.
Researchers found that people suffering from the same injury either recovered or developed chronic pain, depending how two sections of their brains communicated with each other.
The Northwestern study, the first longitudinal brain imaging study to track patients with a new back injury, included 40 participants with no prior history of back pain who had an episode of back pain lasting four to 16 weeks. Brain scans were conducted on each patient during the one year study.
The study, published in the journal Nature Neuroscience, found that the more two sections of the brain relating to emotional and motivational behavior “talk” to each other, the more likely the patient would develop chronic pain. Researchers were able to predict with 85 percent accuracy which participants would develop chronic pain, depending upon the level of interaction between the brain’s frontal cortex and the nucleus accumbens.
“For the first time we can explain why people who may have the exact same initial pain either go on to recover or develop chronic pain,” said A. Vania Apkarian, senior study author and professor of physiology at Northwestern University Feinberg School of Medicine. “The injury itself is not enough to explain the ongoing pain. It has to do with the injury combined with the state of the brain.”
Apkarian says that the more emotionally the brain reacts to the initial injury, the more likely the pain will persist after the injury has healed.
“It may be that these sections of the brain are more excited from the start in certain individuals, or there may be genetic and environmental influences that predispose these regions to interact at an excitable level,” Apkarian said.
According to a 2011 National Academy of Science report, intractable pain affects 30 to 40 million adults, costing theUnited States$600 billion a year. Back pain is the most common chronic pain condition.
“Chronic pain is one of the most expensive health care conditions in the United States, yet there still is not a scientifically validated therapy for this condition,” said Apkarian. “Now we hope to develop new therapies for treatment based on this finding.”
Another recent study found that mental distractions inhibit responses to the earliest stage of pain signals in pain-sensitive cortical and subcortical sections of the brain. Distractions also affect endogenous opioids, which are naturally produced by the brain and play a key role in pain relief.