From the National Council for Behavioral Health:
“Mass Violence in America: Causes, Impacts and Solutions” provides important insights into the link between mental illness and mass violence. The National Council’s Medical Director Institute authored the report.
According to the report, “people with serious mental illness are responsible for less than 4 percent of all violence and less than one-third of mass violence.” Statistics bear out that most people who commit mass violence do not have a serious mental illness.
Read the full report, Mass Violence in America: Causes, Impacts and Solutions, or take a look at the executive summary.