– About 30 million to 40 million American adults suffer from chronic pain—but it may be all in their heads, a new study says. Researchers looked at 40 volunteers, all back pain sufferers, and found that brain scans could predict with 85% accuracy whether their pain would become chronic. At issue is the emotional response to injury and the relationship between two brain regions, the nucleus accumbens and the frontal cortex, the Telegraph reports. When these brain regions—related to motivational and emotional behavior—get to talking, the odds increase that pain will become chronic, explains PsychCentral. ''The injury itself is not enough to explain the ongoing pain,” says the study's lead researcher. "It has to do with the injury combined with the state of the brain.'' But while brain scans did connect chronic pain to communication levels in the brain, they did not establish a causal link, notes Health Day News.