Men and Women Experience Pain Differently: New Study Highlights Need for Sex-Specific Pain Treatments

Chronic pain affects millions of people worldwide, and women are disproportionately more likely to experience it than men. This gender disparity in pain experiences has long been recognized, but the underlying biological reasons behind it remain elusive. A groundbreaking study from the University of California San Diego School of Medicine sheds light on this mystery, revealing that men and women utilize distinct biological pathways for pain relief.

The study, published in PNAS Nexus, focused on meditation as a potential treatment for chronic lower back pain. Researchers discovered that men primarily rely on the release of endogenous opioids – the body’s natural painkillers – to manage pain. In contrast, women appear to depend on alternative, non-opioid mechanisms.

This finding has significant implications for understanding why women often respond poorly to opioid-based pain medications. These drugs, including morphine and fentanyl, work by mimicking the effects of endogenous opioids. If women’s pain relief mechanisms are less reliant on opioids, they may require higher doses to achieve the same effect, increasing the risk of dependence and addiction.

“Dependence develops because people start taking more opioids when their original dosage stops working,” explains Fadel Zeidan, Ph.D., professor of anesthesiology and Endowed Professor in Empathy and Compassion Research at UC San Diego Sanford Institute for Empathy and Compassion. “Although speculative, our findings suggest that maybe one reason that females are more likely to become addicted to opioids is that they’re biologically less responsive to them and need to take more to experience any pain relief.”

Study Design and Key Findings

The study involved two clinical trials with a total of 98 participants, including both healthy individuals and those with chronic lower back pain. Participants underwent a meditation training program and then practiced meditation while receiving either a placebo or a high dose of naloxone, a drug that blocks both synthetic and endogenous opioids. During this process, they experienced a controlled, painful heat stimulus to the back of the leg.

The researchers found several key takeaways:

• In men, blocking the opioid system with naloxone significantly reduced the pain relief experienced during meditation, indicating a reliance on endogenous opioids for pain management.
• In women, naloxone actually increased the pain relief they gained from meditation, suggesting they utilize non-opioid pathways for pain reduction.
• Both men and women with chronic pain reported more pain relief from meditation compared to healthy participants.

“These results underscore the need for more sex-specific pain therapies, because many of the treatments we use don’t work nearly as well for women as they do for men,” says Zeidan.

The Future of Pain Management

This groundbreaking study provides compelling evidence for tailoring pain treatments based on an individual’s sex. By understanding the distinct biological mechanisms involved in pain perception and relief, researchers can develop more effective and targeted therapies for both men and women. This could potentially reduce the reliance on opioids, mitigate the risk of addiction, and ultimately improve patient outcomes for all.

Learn more about pain management research and resources at the National Center for Complementary and Integrative Health: https://www.nccih.nih.gov/