Opioid abuse -- United States -- Simulation, Opioid abuse -- Treatment, System analysis
Background: The U.S. opioid epidemic has caused substantial harm for over 20 years. Policy interventions have had limited impact and sometimes backfired. Experts recommend a systems modeling approach to address the complexities of opioid policymaking.
Objectives: Develop a system dynamics simulation model that reflects the complexities and can anticipate intended and unintended intervention effects.
Methods: The model was developed from literature review and data gathering. Its outputs, starting 1990, were compared against 12 historical time series. Illustrative interventions were simulated for 2020-2030: reducing prescription dosage by 20%, cutting diversion by 30%, increasing addiction treatment from 45% to 65%, and increasing lay naloxone use from 4% to 20%. Sensitivity testing was performed to determine effects of uncertainties. No human subjects were studied.
Results: The model fits historical data well with error percentage averaging 9% across 201 data points. Interventions to reduce dosage and diversion reduce the number of persons with opioid use disorder (PWOUD) by 11% and 16%, respectively, but each reduces overdoses by only 1%. Boosting treatment reduces overdoses by 3% but increases PWOUD by 1%. Expanding naloxone reduces overdose deaths by 12% but increases PWOUD by 2% and overdoses by 3%. Combining all four interventions reduces PWOUD by 24%, overdoses by 4%, and deaths by 18%. Uncertainties may affect these numerical results, but policy findings are unchanged.
Conclusion: No single intervention significantly reduces both PWOUD and overdose deaths, but a combination strategy can do so. Entering the 2020s, only protective measures like naloxone expansion could significantly reduce overdose deaths.
Pre-print citation: Jack Homer and Wayne W. Wakeland. (2020) "A Dynamic Model of the Opioid Drug Epidemic with Implications for Policy." https://archives.pdx.edu/ds/psu/32340 Published version citation: Homer, Jack and Wakeland, Wayne. "A Dynamic Model of the Opioid Drug Epidemic with Implications for Policy." American Journal of Drug and Alcohol Abuse, June 2020. https://www.tandfonline.com/doi/full/10.1080/00952990.2020.1755677. Supplemental material (Appendix) at: https://www.tandfonline.com/doi/suppl/10.1080/00952990.2020.1755677.