Central sensitization complicates chronic pain treatment, opioid use disorder

Central sensitization may be an important underlying factor that complicates the treatment of chronic pain and opioid use disorders, researchers wrote in PAIN Reports.

Orman Trent Hall, DO, an osteopathic physician and addiction psychiatrist at Ohio State University’s Wexner Medical Center, and colleagues recruited participants with opioid use disorders (OUD) from an academic addiction treatment center in Columbus, Ohio, to assess the relationship between OUD and chronic pain.

“It’s important to me to search for new ways to help,” Hall said in a release from the university. “But we can’t create better treatments for chronic pain and OUD without first understanding how the two relate. I did this study because I believed it might offer a new window into what is happening in the brains of patients needing help with pain and addiction.”

Central sensitization refers to abnormal pain processing in the brain and spinal cord, the release stated. Those with central sensitization have spinal cords that are good at sending pain signals to the brain, and brains often struggle to turn said signals off, suggesting that those with a greater central sensitization tend to suffer more with pain than others.

Hall and colleagues enrolled a total of 141 individuals for the study. The study participants were electronically administered the American College of Rheumatology 2011 Fibromyalgia Survey. They also responded to questions about pain interference and quality of life, as well as items regarding pain beliefs and expectations of pain and addiction treatment.

Of all of the participants, 125 (88.7%) reported at least one painful body region. Pain was often reported in the low back (70.2%), neck (31.9%) and upper back (30.5%). The scores of 39 participants (31.2%) were consistent with the diagnosis of fibromyalgia.

Correlational analyses showed relationships between central sensitization, pain interference and health-related quality of life among all participants. The degree of central sensitization was positively correlated with greater endorsement of pain as the reason for onset, maintenance and escalation of OUD; treatment delay; and relapse.

“Our study is the first to give patients with OUD a scale that measures central sensitization,” Hall said. “Our study provides the first evidence of central sensitization underlying the chronic pain and OUD relationship and demonstrates a new tool for easily measuring central sensitization among individuals with OUD.”

According to Daniel J. Clauw, MD, co-author of the study and the director of the Chronic Pain and Fatigue Research Center at the University of Michigan, “patients higher in central sensitization were more likely to report pain as a major reason for why their opioid addiction first began, as well as for putting off addiction treatment, continuing and increasing their use of opioids, and fear of pain causing OUD relapse in the future.”

References:

The Ohio State University, Wexler Medical Center. Press release: Study provides first evidence of link between opioid use disorder, chronic pain. Published July 11, 2022. Accessed July 12, 2022.