Chronic pain is often described as a radio blaring at full volume with no way to turn it down. Opioids lower that volume, but they also rewire other parts of the brain—leading to dependence, overdose, and death. Now researchers have found a way to turn down just the pain signal.
A new gene therapy approach, published in Nature by teams at the University of Pennsylvania, Carnegie Mellon, and Stanford, acts like a precision volume control for the brain. Instead of dulling all sensation the way morphine does, it targets only the circuits that process pain, leaving the rest of the brain untouched.
"The goal was to reduce pain while lessening or eliminating the risk of addiction and dangerous side effects," says Gregory Corder, assistant professor of psychiatry and neuroscience at Penn and co-senior author of the study. "By targeting the precise brain circuits that morphine acts on, we believe this is a first step in offering new relief for people whose lives are upended by chronic pain."
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About 50 million Americans live with chronic pain. The economic toll is staggering—over $635 billion annually in medical costs and lost productivity. But the human cost is what's driving this research. In 2019 alone, 600,000 deaths were attributed to drug use, with opioids responsible for 80 percent of them. In Philadelphia, nearly half of people surveyed in 2025 knew someone with opioid use disorder. One-third knew someone who had died from an overdose.
The team developed their approach using advanced brain imaging and AI-guided behavioral analysis in animal models, testing over six years with support from a National Institutes of Health New Innovator Award. They identified the specific neural circuits where opioids work—and where they cause harm—then designed the gene therapy to affect only the pain-processing regions.
This is still preclinical work. The journey from lab discovery to human trials is long, and there's no guarantee this will translate perfectly to people. But the researchers are moving into the next phase of development with Michael Platt, the James S. Riepe University Professor at Penn, leading the way toward clinical trials.
"Speaking both as a scientist and as a family member of people affected by chronic pain, the potential to relieve suffering without fueling the opioid crisis is exciting," Platt says.
If it works, this could reshape how we treat one of the most common sources of human suffering—without creating a new one.
