According to the World Health Organization, suicide is a leading cause of death globally with over 800,000 annual deaths (World Health Organization, 2019). In the United States, roughly 46,500 adults died by suicide in 2018, including over 6,400 veterans (Department of Veterans Affairs Office of Mental Health and Suicide Prevention, 2020). Since the Department of Veterans Affairs (VA) began to publicly share their records of veteran suicide in 2005, the suicide rates among veterans have outpaced those of nonveterans in the United States through 2018, adjusting for age and sex (Curtin, 1995; Department of Veterans Affairs Office of Mental Health and Suicide Prevention, 2020). Notably, suicide comprises a complex public health problem composed of multiple environmental and biological factors that interact at the individual, community, and institutional levels. As such, much work has been done to develop theoretical frameworks that account for these multilevel risk and protective factors and assist in structuring empirical research to inform evidence-based suicide prevention services (Chu et al., 2017).One such framework is the Interpersonal Theory of Suicide (ITS), which outlines causal pathways to suicidal behaviors (Joiner, 2005;Van Orden et al., 2010). Specifically, the theory speaks to how thwarted belongingness, perceived burdensomeness, and capability for suicide intersect to influence an individual's suicide risk (Joiner, 2005;Van Orden et al., 2010). Expanding on ITS, the Eusocial Theory posits that humans rely on a division of labor, with distinct groups whose individual roles contribute to the survival of the community as a whole. One such group is called "eusocial defenders," whose purpose it is to protect and defend the greater community (Joiner et al., 2016). In this paper, the authors suggest that, among humans, military service members, veterans, and first responders may be predisposed to hold characteristics of eusocial defenders. Specifically, the authors advocate that eusocial defenders may have a biobehavioral tendency for self-sacrifice as well as self-assessment based on their This article was published Online First October 21, 2021.
