Background: This paper argues that the decline in the availability of long-term, intensive mental health services, particularly through state mental health hospital systems, has had negative impacts on firearm-related deaths and possibly on the incidence of mass shooting events.
Aims: Establish the effect of reduced availability of long-term, intensive mental health treatment on firearm-related violence in the United States.
Method: Ordinary least squares regressions on cross-sectional data of US states.
Results: Mass shooting perpetrators had significantly higher rates of mental illness than the general population. In addition, using simple regressions, this paper's results demonstrate that increasing the number of state psychiatric hospital beds is associated with lower rates of homicide.
Conclusions: The shrinking number of intensive, long-term mental health facilities in US states has had many negative consequences, including higher rates of firearm homicide.
Keywords: State psychiatric hospitals; firearm violence; mental healthcare.