Environmental enrichment found to weaken stress-triggered fentanyl relapse

Combating the opioid crisis relies on identifying new prevention strategies for problematic fentanyl use. In a collaboration between Washington State University and Washington University in St. Louis, researchers led by Jose Moron tested whether enriching a rat's environment can reduce fentanyl use and relapse. 

The researchers housed rats individually in either standard conditions or environments with new objects and measured fentanyl use across stages modeling human addiction: ongoing use, quitting, and relapse triggered by stress. Environmental enrichment reduced fentanyl intake over time and helped animals stop seeking the drug faster. Notably, when exposed to a stressful trigger, rats in enriched environments showed a much weaker relapse response compared to those in standard conditions. Rats in enriched environments also had lower levels of stress hormones, which were linked to relapse in those with standard conditions. 

According to the researchers, their work suggests that supplying rats with new objects in nonsocial environments can protect against fentanyl use and relapse. Says Jose Moron-Concepcion, "Because these strategies do not rely on social interaction, they may be easier to implement in real-world settings, including treatment programs and recovery environments. More broadly, this work highlights the powerful role of the environment and stress in addiction. Enrichment-based approaches could complement existing treatments and offer a scalable way to reduce opioid use and relapse risk."