Pain is the human bodyguard, the cop on the beat racing to the scene, sirens wailing, shutting down traffic. You’ve been cut, burned, broken: pay attention, stop the bleeding, apply heat, apply cold, do something. It’s one of life’s most primitive mechanisms, by which even the simplest creature, if it has anything like a central nervous system, learns to avoid danger, stay out of bad neighborhoods, hunker down to give itself time to heal. Pain is protective. Don’t do that, it commands — and the command is usually a wise one. So this sensation we seek most to avoid is in fact one of the most essential ones for our survival.
But what happens when pain goes rogue, when it sends off false alarms so that all the sirens keep sounding, all the cops keep coming, all the hurts keep hurting? If even benign stimuli get distilled down to a single, primal Ouch!, then pain ceases to be adaptive. Rather than saving lives, it wrecks them. Rather than helping you get well or stay safe, it becomes an illness in itself. The result: persistent, unceasing torment.
That’s the situation that more than 76 million Americans face. Their pain can last for days or even weeks at a time, then dissipate, only to return. The problem may be caused by something as common as arthritis, an inflammation of the joints that makes them throb with discomfort. The issue could be fibromyalgia, in which a breakdown of pain signals leaves joints, muscles and tissues hypersensitive. It may be a nerve disorder known as neuropathy, triggered by diseases as diverse as cancer and diabetes. It may be that the cause is unidentifiable. Many cases of chronic pain remain unexplained, but they hurt all the same.
There’s no telling who the victims of chronic pain will be, but there are ways of determining who is at highest risk. About 10% of people who have surgery, even relatively routine procedures such as knee or back operations, for example, will never be the same again, suffering a lifetime of generalized pain that may start from the incision site but is eventually diffused to other parts of the body. Around 20% of cancer patients will continue to feel pain two years after the surgery or chemotherapy that may have saved their lives. For all of them, pain is not merely a symptom but a disease in itself, one that doctors have only recently come to recognize.
