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16 Articles in Volume 19, Issue #2
Analgesics of the Future: Inside the Potential of Glial Cell Modulators
APPs as Leaders in Pain Management
Cases in Urine Drug Monitoring Interpretation: How to Stay in Control
Complex Chronic Pain Disorders
Efficacy of Chiropractic Care for Back Pain: A Clinical Summary
Hydrodissection for the Treatment of Abdominal Pain Caused by Post-Operative Adhesions
Letters: The Word "Catastrophizing;" AIPM Ceases Operations; Patient Questions
Management of Severe Radiculopathy in a Pregnant Patient
Managing Pain in Adults with Intellectual Disabilities
Pain in the Courtroom: An Excerpt
Q&A with Howard L. Fields: How Patients’ Expectations May Control Pain
Special Report: CGRP Monoclonal Antibodies for Chronic Migraine
The Management of Chronic Overlapping Pain Conditions
Vibration for Chronic Pain
What are the dangers of loperamide abuse?
When Patient Education Fails to Improve Outcomes: A Low Back Pain Case

Q&A with Howard L. Fields: How Patients’ Expectations May Control Pain

UCSF Neurologist Howard L. Fields, MD, PhD, on pain signals, decision-making, and optimism.
Page 17

Professor emeritus of neurology at the University of California San Francisco, Howard L. Fields, MD, PhD, has been studying how endogenous opioids contribute to nervous system mechanisms of pain and substance abuse. He was a founder of the UCSF pain management center and has made major contributions to understanding and treating neuropathic pain. Here, he answers a few questions about his most recent paper1 on how patient expectations may influence pain.

Patients' Decision-Making

PPM: In individuals with chronic pain, brain signals are constantly telling them something is wrong. As a result, they are less likely to engage in daily activities and largely become isolated. How does pain influence their decision-making in these cases?

Dr. Fields: This cycle is an unconscious process. The presence of ongoing pain biases the brain to respond in ways that protect the body from further injury. In everyday life, we are constantly deciding what to do—work on a report, go out to eat, get a good night’s sleep, and so forth. When for example, a person sprains an ankle, the brain says, ‘Protect the ankle,’ which means it is less likely the person will go out to eat unless they are very hungry. The bias toward tissue protection makes all other activities less likely as well, which we observe as becoming isolated and more focused on tissue protection. Unfortunately, the ‘protect tissue’ decision turns up the gain on the pain signal, so the same injury is experienced as more painful, which makes a person even less likely to engage in other activities; this is the downward spiral.

The question around patients with chronic pain is, How realistic is their fear that activity will make their pain worse? There is good evidence that pessimism and what some call ‘catastrophizing’ is part of many pain patients’ suffering and that it, in turn, turns up the pain intensity through top-down brain circuits. In any situation, it is unclear how much of a person’s experienced pain intensity is coming from the tissue injury and how much is coming from their fear or expectation that the activity will worsen the pain. However, it is clear that expectation has a major effect on the intensity of pain with any given degree of tissue injury. If more pain is expected, more is experienced and vice-versa when less pain is expected.

Since many chronic pain patients expect to have pain each day, I am an optimist if the injury or disease causing the pain is static. I am optimistic because, to the extent that expectations can be changed, the patient can experience relief without surgery or medication. This type of treatment is free of adverse effects and its impact on pain relief may actually increase over time. Of course, the expectation component is highly variable from individual to individual.

PPM: Pain pathways are meant to be useful by helping humans to avoid damaging their bodies when an injury occurs or is imminent. But in those with chronic pain, the pain signal may be considered dysfunctional. Is there an identifiable point when this shift from functional to dysfunctional occurs? How could this knowledge about the pain transmission system aid in preventing pain chronification?

Dr. Fields: The pain signal itself is not dysfunctional, but rather, it contains a signal that is two-fold: one is the damage that has just occurred; the other (generated by the brain) is a prediction that there will be future damage. If patients can learn to differentiate these two functions and believe that the pain generator is static (ie, the brain’s prediction of more pain is not accurate), then they may continue to have a pain signal input (eg, arthritis of the hip) but it will be experienced as less painful.

This understanding may allow them to be more functional and more engaged in things they enjoy doing. For example, with musculoskeletal low back pain, there is evidence that, after an initial brief period of rest, increasing physical activity will actually accelerate functional recovery and lower pain. The decision to stay in bed and refrain from normal activity is counterproductive and can lead to more pain.

Could Simple Optimism Influence Pain Response?

PPM: In separate but related research,2* faculty at the Universities of Michigan and Pennsylvania, and at the Army Analytics Group’s Research Facilitation Laboratory in Monterrey, studied how pain impacts soldiers after deployment, with a novel focus on protective factors. They wanted to see if predeployment optimism could affect response to the onset of new pain after deployment.

The prospective longitudinal cohort study analyzed the data of nearly 21,000 (87.8% male; mean age: 29) eligible soldiers deployed between approximately February 2010 and August 2014 using existing, secondary Army data. Soldiers had completed the necessary psychological and health assessments before and after deployment. Post-deployment reports of pain, including new back pain, joint pain, and frequent headaches, were examined.

Among the sample, 37% reported pain in at least one new area of the body after deployment: 25% reported new back pain, 23% reported new joint pain, and 12% reported new frequent headaches. According to the published review, tertile analyses revealed that, “compared with soldiers with high optimism (lowest odds of new pain) soldiers with low optimism had 35% greater odds of reporting new pain in any of the three sites evaluated” (OR, 1.35; 95% CI, 1.21-1.50). “In addition, a larger increase in risk of new pain was observed when comparing the moderate-optimism and low-optimism groups rather than the high-optimism and moderate-optimism groups.”

Overall, researchers determined that “higher levels of optimism were associated with lower odds of reporting new pain.” They recommended that soldiers expressing low levels of optimism prior to deployment might benefit from optimism-enhancing programs.

Dr. Fields: These findings fit with extensive evidence that depression increases the risk of chronic pain and that chronic pain patients score higher on standard scales of depression. While antidepressants can have analgesic effects in non-depressed patients, I believe that part of their benefit on a broad range of chronically painful conditions is through relief of depression, which reduces pessimism.

*Percentages/numbers estimated. See full study for exact data.

Last updated on: April 22, 2019
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