Date of Conferral





Public Health


Priscilla N. Chukwueke


AbstractWhenever a mass shooting occurs, it impacts the immediate families of the perpetrator, victims, and the whole nation: emotionally and financially. The research on the association between mental illness (MI) and mass shooting fatalities is limited. The purpose of this quantitative, cross-sectional study was to explore the association between MI and mass shooting using the archival data of the Stanford University database of mass shootings in America from 2000 to 2016. The theoretical framework was based on Bronfenbrenner’s social-ecological theory and the cognitive-behavioral theory to explain socio-environmental factors that impact human growth and development. The results showed that the proportion of mass shooters with MI (42.1%) was significantly greater than the proportion of the general population with MI (18.9%), Z = -1137.72, p<.0001. Shooters with MI have caused a significantly higher number of fatalities than those without MI, t (61.71) = 3.10, p<.01. Conversely, among mass shooters, there is no association between MI and type of killing, X² (7) = 13.72, p = .056. A chi-square analysis indicated that MI was not significantly related to the type of gun used in the shooting, X² (4) = 4.34, p = .36. Lastly, study participants with MI evidenced a significantly higher number of fatalities relative to those without MI, B = 2.05, SE = .86, β = .23, p<.05. The study has implications for social change: the findings can guide policymakers to fund research (a) to identify associations between MI and mass shootings and (b) on the need for more legislation and/or gun accident prevention programs to decrease mass shootings.