Editor’s Note: The second North American Pain School (NAPS) took place June 25-29, 2017, in Montebello, Quebec, Canada. This educational initiative brought together leading experts in pain research and management to provide 30 trainees–part of the up-and-coming generation of pain researchers–with scientific education, professional development and networking experiences. Six of the trainees were also selected to provide first-hand reporting from the event, including summaries of talks presented at the meeting. Here, Shana Burrowes, a graduate student and epidemiologist at the University of Maryland, summarizes a talk delivered by Jennifer Haythornthwaite, a pain psychologist at Johns Hopkins University. Haythornthwaite’s talk focused on the role of catastrophizing in chronic pain.
People who suffer from chronic pain know that very often the pain is not the worst part. Instead, the effect of pain on functioning—the challenge of just making it through the day—is much more burdensome.
How people cope with their pain and poor functioning was the focus of a talk at the North American Pain School by Jennifer Haythornthwaite, a pain psychologist at Johns Hopkins University in Baltimore. The take-home message of her presentation, entitled “Thinking Inside and Outside the Box About Psychosocial Factors,” was for researchers and physicians alike to approach pain differently. They need to recognize that pain is very much a psychological and social experience with complicated origins that are still not well understood. From this perspective, Haythornthwaite focused on pain catastrophizing, an important emotional component of pain that plays a significant role in the pain experience.
What is pain catastrophizing?
Individuals differ in how they perceive pain, and in how they react to any painful experience. Some can work through the pain and make it through the day, while others think about their pain constantly, worry about when it will end and how much worse it will get. This negative emotional response to pain is called pain catastrophizing, a subject of much of Haythornthwaite’s research.
Pain researchers measure pain catastrophizing using a scale that captures three main components: rumination, magnification and helplessness. Patients with chronic pain who ruminate may say, “I worry about whether the pain will end.” Patients who magnify their pain may remark, “I keep thinking about how much it hurts,” while those who feel helpless about their pain might state, “It’s awful and I feel that it overwhelms me.”
Patients who score high on the catastrophizing scale have poorer clinical outcomes in the short and long term, reporting less improvement in pain and physical functioning.
The role of catastrophizing in the response to pain treatment
Studies show that patients who catastrophize a lot respond poorly to pain treatment. For instance, a 2014 study published in the Journal of Pain Research assessed catastrophizing in patients with pain from nerve injury (neuropathic pain) who received drugs for their condition. For the 62 subjects who took part in the study, treatment was deemed successful if there was at least a 30% improvement in pain at three or six months of follow up.
Results showed that higher levels of catastrophizing were associated with a poorer response to treatment, a higher likelihood of discontinuing treatment, and poorer quality of life.
Research in other pain populations has shown that catastrophizing persists over time even when there has been successful treatment and predicts whether treatment will be successful or not. For example, in a study published in 2009 in the journal Pain Research and Management, of 43 osteoarthritis patients who underwent total knee replacement surgery and were followed for a year, catastrophizing scores remained unchanged even after the surgery helped to relieve their pain. In addition, those with higher pain catastrophizing and depression reported more pain.
Along similar lines, in a study published in 2004 in the Journal of Pain that looked at 46 patients with acute dental pain, results indicated that patients catastrophized to the same degree even when no longer experiencing pain. This study also examined how sensitive the patients were to experimentally applied heat—a common way to assess pain in laboratory studies. The more that patients catastrophized, the more sensitive they were to heat even after their dental pain had been relieved.
Such studies suggest to researchers that in some respects catastrophizing may be a stable trait that not only predicts how well patients will cope with future pain but how they will respond to treatment. However, physicians could potentially intervene to reduce levels of catastrophizing before administering treatment, in order to increase the likelihood that therapies will relieve pain.
Studying pain catastrophizing in the lab
To better understand pain catastrophizing, researchers like Haythornthwaite study not only pain patients but also healthy individuals who are subjected to pain in laboratory studies. In such studies, one area of research she has pursued examines the role of situational catastrophizing and whether the findings from those investigations can further the understanding of pain catastrophizing in patients. Situational catastrophizing is catastrophizing that is measured either during or after being exposed to a painful stimulus in the lab.
For example, one of Haythornthwaite’s studies published in 2010 in the Journal of Pain measured situational catastrophizing and pain intensity at three different time points in 38 healthy individuals who received a cream containing capsaicin (the ingredient in chili peppers that makes them hot). Results showed that changes in catastrophizing during the course of the study predicted how much pain participants reported in response to the cream: those who had the biggest initial increase in catastrophizing had the biggest subsequent increase in pain.
These findings are important because it hasn’t always been clear if pain makes people catastrophize or if catastrophizing leads to pain. This study showed that changes in catastrophizing came before changes in pain, at least in this sample of healthy people.
Learning more from patients
What else have researchers learned from patients about the role of catastrophizing in pain? In a 2003 clinical trial of patients with post-herpetic neuralgia (PHN), a condition where patients suffer pain due to nerve damage after an outbreak of shingles (which is caused by reactivation of the virus that causes chicken pox), catastrophizing predicted whether pain would persist in those individuals in the future. In another study published in 2011, catastrophizing was also found to predict the development of chronic pain after surgery.
While catastrophizing has been shown to predict future pain to a moderate degree, how much catastrophizing a person engages in has varied depending upon which patient population is under study. This may be due to the severity of illness, how long a person has suffered from pain, or the setting in which the patient was treated.
Searching for an explanation
What explains the link between catastrophizing and pain? While this is still not well understood, there are three main factors that pain researchers have focused on in this regard: poor coping, the biological stress response and poor endogenous pain modulation.
Poor coping refers to the difficulties that people who are high catastrophizers have in using certain strategies to deal with their pain. For example, in a 2010 study from Haythornthwaite and colleagues in which subjects played video games to distract them from their pain, high catastrophizers took longer to report that their pain was reduced by playing the games.
The biological stress response refers to the body’s production of hormones when under stress. In one study published in 2010, researchers found that catastrophizing was associated with how much cortisol, a stress response hormone, was produced in the saliva in response to experimental pain testing in the laboratory. This was true both of patients with jaw pain and in healthy individuals used as a control group.
Finally, endogenous pain modulation is the ability of a person to naturally inhibit pain. A 2009 study found that high pain catastrophizers had poor endogenous pain modulation. This led them to report more pain in response to pressure and cold temperature, two types of experimental pain often tested in the laboratory, compared to those who did not catastrophize as much.
Many questions still linger about pain catastrophizing. For instance, while there has been some research indicating a genetic component underlying this phenomenon, how environmental factors such as early exposure to pain, poverty, and education affect the development of catastrophizing remains unclear.
Still, there are several consistent findings that reveal the importance of catastrophizing in chronic pain. Catastrophizing is a relatively stable trait whose magnitude differs from patient to patient, and also depends on the type of pain from which patients suffer as well as the setting in which they are evaluated. It also consistently predicts future pain, as well as whether treatments for pain will be successful. This current knowledge provides a framework for future studies so researchers can learn more about the importance of catastrophizing in chronic pain.
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