Current Knowledge on Potential Determinants of Mass Public Shooting Perpetration and Casualties: A Systematic Review

Background In the United States, mass shootings can be regarded as a public health issue due to its ubiquitous and public nature. A systematic review of the literature with adoption of the social ecological model for interpretation of the evidence can help inform relevant stakeholders and the public regarding the coherence between proposed gun control legislations and the body of empirical evidence. Aims To conduct a systematic review of factors associated with: 1) perpetration of mass shooting events, and; 2) injuries and fatalities at mass shooting events. Material and Methods The author conducted a search of the literatures on PubMed using the term “mass shooting”, filtering manuscripts from 2017 to 2022. The author included only articles in peer-reviewed academic journals with primary data collection for the review. Results The author reviewed 36 of the 336 articles initially found from a search on PubMed. All but two studies focused on mass shootings in the United States. Factors associated with perpetration of mass shootings included having mental illness and experience of acute life stressors (intra-personal), relationship issues with family and friends (inter-personal), gun ownership and access (community), permissive firearm laws or lack of gun control (policy). Factors associated with injuries and fatalities at mass shootings included use of semi-automatic rifles (intrapersonal), targeting women (interpersonal), presence of armed officers at schools (organizational), and lack of gun control measures (policy). Conclusion The author found that easy access to high-power firearms and lack of gun control were associated with both mass shooting perpetration and casualty. However, caveats including a limited time frame, limited sources of publications, and subjectivity in building the model should be considered in the interpretation of the study findings.