According to the people who count up stuff like this, more than a billion people around the world suffer chronic pain. "Chronic pain" here means pain that is either unrelated to obvious physical injury or lasts long after the obvious damage has healed, and that lasts at least two months. Chronic pain is a slow-moving medical catastrophe and also big business, which explains why there have been a ton of studies about what causes it.
Today's NY Times has a story about the role of glial cells in pain. One the one hand it is interesting biomedically, as we figure out that the cells we used to think just served as scaffolding for neurons actually do a lot of other stuff. One the other it suffers from the weird obsession with proving that chronic pain has some identifiable physical cause and is not just "in your head." Like this:
For pain sufferers, this is a welcome validation of their reality. “Learning this,” said Cindy Steinberg, the national director of policy and advocacy at the U.S. Pain Foundation, and a chronic pain patient herself, “is enormously helpful to those of us who suffer chronic pain.” In a chronic-pain support group Ms. Steinberg runs, she said that people find it a huge affirmation to learn there’s a distinct biology underlying their pain. It confirms what they’ve long known but often see doubted by doctors and friends: That their pain is as real as any other.
To which I say, there is no such thing as "unreal" pain. Every thought you have, every feeling no matter how fleeting, is something physical happening in your brain. What else could it be? If your pain were caused by obsessing about how cruelly your mother treated you, that would still be a physical thing, and if glial cells are involved in processing pain, then they would be involved in that pain, too.
On the other hand, even pain with overtly physical causes like stab wounds is also a psychological phenomenon, and some people can control it by modulating their thoughts. Remember that some studies have found petting a dog or cat reduces the sensation of pain more than powerful opiates do. Just as there is no pain that is not physical, there is no pain that is not psychological, because you experience it in your mind.
Very good studies have shown that chronic pain is more likely to strike people who have other stressors in their lives, like a divorce or losing a job. This includes both pain that seems to have an overt physical cause like a ruptured spinal disc and pain that does not. The notion that chronic pain could be entirely caused by some problem with glial cells strikes me as absurd; it is easy to show that for many people it is a symptom of a life out of whack. Which, again, does mean that it is not physical, because everything in your mind is physical, or that it could simply be wished away.
At a theoretical level we have understood the complex connections between mind and body at least since Hippocrates. But people keep acting like they are completely separate things, and newspapers where people ought to know better keep publishing stories about entirely imaginary distinctions between things in your mind and things going on with your nerve cells.