Approximately 100 lives are lost each day as a result of gun violence in the United States (US) with civilian mass shootings increasing annually. The gun violence rate in the US is almost 20 times higher than other comparable developed countries and has the most gun ownership per capita of any nation in the world. Understanding the causes and risk factors are paramount in understanding gun violence and reducing its incidence.

A literature search of all published articles relating to gun violence and mass shootings in the US was conducted using the Medline and PMC databases. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were used in conducting this study. Rayyan statistical software was utilized for analysis. Statistical significant was defined as p < .05.

Of the initial 2304 eligible manuscripts identified, 22 fulfilled our selection criteria. A variety of common causal and contributory factors were identified including but not limited to mental illness, suicidal ideation, intimate partner violence, socioeconomic status, community distress, family life, childhood trauma, current or previous substance abuse, and firearm access.

Gun violence is pervasive and multi-factorial. Interventions aimed at reducing gun violence should be targeted towards the most common risk factors cited in the literature such as access, violent behavioral tendencies due to past exposure or substance abuse, and mental illness including suicidal ideation.