A new study has uncovered that men and women use different biological systems to alleviate pain, highlighting the need for sex-specific pain therapies and offering new insights into opioid dependence.
Researchers led by the University of California San Diego School of Medicine have made a significant breakthrough in understanding pain management, discovering that men and women employ different biological systems to relieve pain. This revelation could transform the approach to pain therapy and potentially reduce opioid misuse.
The study, focused on chronic lower back pain and meditation, found that men rely primarily on endogenous opioids — natural painkillers released by the body — whereas women use alternative, non-opioid pathways.
Given the ongoing opioid crisis, these findings are particularly relevant. Opioid drugs like morphine and fentanyl are highly effective but pose considerable risks of dependence and addiction.
“Dependence develops because people start taking more opioids when their original dosage stops working,” Fadel Zeidan, a professor of anesthesiology and Endowed Professor in Empathy and Compassion Research at UC San Diego’s Sanford Institute for Empathy and Compassion, said in a news release. “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.”
The study synthesized data from two clinical trials involving 98 participants, including both healthy individuals and those suffering from chronic lower back pain.
The participants underwent meditation training and experienced a painful heat stimulus to the leg, while being administered either a placebo or a high dose of naloxone, a drug that inhibits both synthetic and endogenous opioids.
The researchers then measured the extent of pain relief derived from meditation with and without the opioid system’s interference.
The results were illuminating.
Blocking the opioid system with naloxone significantly reduced meditation-based pain relief in men, indicating their dependence on endogenous opioids.
Conversely, naloxone increased meditation-based pain relief in women, implying their reliance on non-opioid mechanisms for pain relief.
In both sexes, individuals with chronic pain benefited more 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,” Zeidan added.
By customizing pain treatments based on an individual’s sex, health care providers might enhance patient outcomes and reduce the misuse of opioids.
The researchers emphasized that the discovery marks the first clear evidence of sex-based differences in pain processing.
“This study provides the first clear evidence that sex-based differences in pain processing are real and need to be taken more seriously when developing and prescribing treatment for pain,” Zeidan added.
The study is published in the journal PNAS Nexus.