Researchers at WashU Medicine have identified a gene that may help explain why some individuals are more likely than others to develop opioid addiction. The study, led by Tania Lintz, a staff scientist and graduate student at WashU Medicine, in collaboration with Jose Moron-Concepcion, PhD, the Henry E. Mallinckrodt Professor of Anesthesiology and division chief of basic research for WashU Medicine Anesthesiology, builds on human genetic studies suggesting that the gene CNIH3 may influence how opioid use begins and develops over time.
The study was published in Translational Psychiatry on May 5, 2026.
To test the gene’s role, the researchers used a mouse model in which CNIH3 was removed. They then examined how the animals responded to opioids using a fentanyl self-administration experiment — a laboratory method that mirrors aspects of human drug-taking behavior. Mice lacking the gene showed differences in how opioid use began and progressed compared with typical mice. The effects also differed between male and female animals, suggesting that biological sex may influence how the gene shapes addiction-related behaviors.
The findings help connect large-scale human genetic data with biological mechanisms in the brain. By identifying genes that may influence addiction risk, the research could help guide more personalized strategies for preventing and treating opioid use disorder. Understanding the biological factors that make some individuals more vulnerable — or more resilient — may ultimately lead to targeted therapies that improve recovery outcomes and reduce relapse.