Abstract for: Addressing syndemic disparities in problematic alcohol use, violence, and reproductive health: A system dynamics approach

System dynamics is a promising approach for modeling syndemic health issues (e.g., co-occuring mutually causal or synergistically related epidemics). However, syndemic system dynamics models often fail to capture variation in multimorbidity. Identifying effective intervention strategies in complex syndemics, such as co-occurring alcohol use, intimate partner violence, and unintended pregnancy for American Indian/Alaska Native (AIAN) communities, requires careful representation of the way in which these epidemics relate to each other. We developed a stock and flow model that captured alcohol use dynamics among AIAN and non-AIAN women of childbearing age, focusing on interplay between drinking behavior, contraception use, and pregnancy outcomes, including an endogenous violence variable that impacted change in alcohol and contraception use behavior. We tested the impact of a hypothetical intervention for reducing alcohol use, in conditions where violence was and was not targeted for intervention as well. Implementing a strategy that reduced alcohol use without addressing violence created an immediate but temporary decline in problematic drinking. Without further implementation of the intervention, alcohol use rebounded to almost initial levels. However in strategies were violence was also reduced, alcohol use behavior not only decreased further, but these reduced levels were maintained over time. This impact was particularly strong in the AIAN model. For communities and populations that experience multiple and co-occurring health disparities, many interventions that focus on single issues have low efficacy. Clarifying the nature of the relationship between health outcomes, e.g., considering strategies to more effectively model causal comorbid relations between health outcomes within syndemics, can provide important insight into strategies that will more effectively address health disparities.