Chronic pain is a problem that—when healthcare, lost income, and lost productivity are taken into account—is estimated to cost about $100 billion in the United States each year. More than a quarter of Americans age 20 or older, or about 76.5 million people, say they've experienced pain that lasted longer than 24 hours, according to the American Pain Foundation—and 42 percent have endured pain lasting longer than a year. Nobody keeps good long-term national stats, but if North Carolina's experience is any guide, the numbers are on the rise: A just-published study in the Archives of Internal Medicine found that the prevalence of chronic low-back pain in the state more than doubled, to 10.2 percent, between 1992 and 2006. Paul J. Christo, assistant professor and director of the Multidisciplinary Pain Fellowship at the Johns Hopkins University School of Medicine, calls undiagnosed, untreated, or undertreated pain a "significant public-health problem."
Chronic pain encompasses a multitude of ills, from back pain, headaches, neck pain, and conditions like arthritis and fibromyalgia to pain that develops as a result of cancer treatment and lingers for months or even years. Low-back pain, migraines, and joint pain (particularly in the knees) are among the most common complaints, according to the National Center for Health Statistics. Still, while it may have different origins, chronic pain "can be viewed as an illness in its own right because of its effect on function," says Russell Portenoy, chairman of the department of pain medicine and palliative care at Beth Israel Medical Center in New York City.
Studies have shown that some people with chronic pain have brain abnormalities, though the connection between that and pain isn't well understood. One recent study, for instance, showed that women with fibromyalgia had blood flow abnormalities in a region of the brain known to discriminate the intensity of pain that weren't observed on CT scans done in healthy women. Another study showed that chronic pain may harm the wiring of the brain, as demonstrated on functional MRIs. Chronic pain may also be caused by a problem with the "fight or flight" response, Christo says. "We believe that in certain pain conditions . . . the stress response can worsen pain because that stress response releases a chemical called noroepinephrine. . . . And noroepinephrine binds to certain receptors in the body that trigger pain."
"Pain is essentially an alarm system that is designed to grab your attention, and when it works properly, it signals harm or healing," says Scott Fishman, professor and chief of the division of pain medicine at the University of California-Davis School of Medicine. When the body heals, the pain should dissipate, but "the nervous system can become injured," Fishman says. "That's when the symptom of pain becomes the disease of chronic pain."
Finding relief can take quite an effort, since the causes are often not immediately clear and there isn't a sure-fire treatment. The battle can require a team of experts, so the multidisciplinary pain clinics or pain management programs that have sprouted up at hospitals, rehab centers, and in free-standing facilities over the past decade or so may be of particular help. The clinics provide an all-in-one setting for care that, in addition to pain management specialists who may be trained as neurologists, psychiatrists, physiatrists, or anesthesiologists, may include physical therapists, family and vocational counselors, and massage therapists, for example. (The American Chronic Pain Association offers advice on selecting a pain clinic.)
After a full assessment, tailored treatment may include medications from anti-inflammatory drugs to antidepressants to opioids. Since commonly prescribed opioid medications such as oxycodone, fentanyl, and morphine can cause addiction, the American Pain Society and the American Academy of Pain Medicine have just released the first comprehensive clinical practice guidelines to help physicians make treatment decisions. The guidelines, published in the Journal of Pain, suggest that physicians regularly assess people taking long-term opioids and do periodic drug screenings of patients who are considered to be at risk for abuse or addiction. Meanwhile, the Food and Drug Administration announced plans this month to require the brand-name and generic makers of morphine, oxycodone, fentanyl, and methadone to assist with a plan to reduce the risks associated with the drugs.