Navigating Dual-Harm: Integrating Self- and Other-Harm Into Public Health Inquiry

Dual-harm, the co-occurrence of self- and other-harm, recognizes the overlap between these outcomes of aggressive behavior and their potential shared causes. Little progress has been made in preventing and responding to dual-harm in the broader population, and it remains understudied in public health research. We posit that the scientific investigation of dual-harm would greatly benefit from the application of public health principles and methods. In this essay, we operationalize dual-harm as a public health problem and identify gaps in knowledge, addressing its conceptual and definitional issues, prevalence estimates, methodological considerations, theoretical foundations, risk factors, and prevention strategies. We also offer a series of recommendations to advance dual-harm study and challenge the notion of conflating nonfatal dual-harm with homicide-suicide as part of a continuum, arguing that they are distinct phenomena. We identify the need for epidemiological studies to characterize those engaging in dual-harm and better understand their mechanisms and outcomes, focusing on adolescence as a critical developmental period. Future studies should develop, implement, and evaluate targeted intervention and preventive efforts for individuals involved in or at risk for dual-harm. (<i>Am J Public Health</i>. 2025;115(4):596-604. https://doi.org/10.2105/AJPH.2024.307940).