Environmental Enrichment Attenuates Fentanyl-Seeking Behavior and Protects Against Stress-Induced Reinstatement in Both Male and Female Rats

This study demonstrates that long-term, object-based environmental enrichment in the absence of social peers is sufficient to reduce fentanyl intake and blunt stress-induced reinstatement in male and female rats. These findings identify a simple, scalable environmental intervention capable of dampening both drug use and vulnerability to relapse triggers. Given the prevalence of individuals exposed to periods of social isolation or with limited access to support, understanding how non-peer-based enrichment influences maladaptive opioid use and stress reactivity is of timely and translational importance. The ability of enrichment to reduce corticosterone, fentanyl consumption, and drug-cue reactivity highlights the importance of environmental context in shaping opioid misuse liability and implicates novel and practical avenues for relapse prevention.