Abstract for: A Systems Perspective on Stimulant-Involved Overdose Deaths: Evaluating Dynamic Hypotheses

Background: The overdose epidemic in the United States is evolving, as both stimulant-only and stimulant and opioid-involved overdose deaths are rapidly rising, with the underlying reasons remaining unclear. Methods: We employed a community-based system dynamics approach, conducting semi-structured individual interviews and group model-building workshops in Massachusetts and South Dakota. These locations serve as case studies, allowing us to extract dynamic hypotheses that seek to explain these distinct trends, which are visualized through stock-flow diagrams. Results: For stimulant and opioid-involved overdose deaths, we identified three dynamic hypotheses: (1) contamination of stimulants with fentanyl is leading to overdose deaths among stimulant-only users; (2) stigma leads to underreporting of opioid use undermining harm reduction efforts (3) polysubstance use is increasing among opioid users, resulting in more frequent detection of stimulants in overdose deaths. For stimulant-only overdose deaths, we identified three dynamic hypotheses: (1) autopsy toxicology data is inaccurate, and overdoses involving both stimulants and opioids are misclassified as stimulant-only due to undetected fentanyl; (2) the potency of stimulants is increasing, leading to more fatal overdoses; and (3) stimulant users are aging or developing underlying health conditions over time, exacerbating the risk of fatal overdoses. Conclusions: While individual dynamic hypotheses have their limitations, collectively, they provide a holistic understanding that can guide public health interventions and policy responses.