Are video games or mental illness causing America’s mass shootings? No, research shows.

Every time a mass shooting occurs, the country talks about mental health. Many politicians are quick to point to the shooters’ disturbed minds. News reporters probe for “loner” tendencies or signs of instability.

“Mental illness and hatred pull the trigger. Not the gun,” said President Trump on Monday, after two mass shootings in less than 24 hours. So is mental illness to blame for America’s mass shootings? Not according to research.

Some mass shooters have a history of schizophrenia or psychosis, but many do not. Most studies of mass shooters have found that only a small fraction have mental health issues. And researchers have noted a host of other factors that are stronger predictors of someone becoming a mass shooter: a strong sense of resentment, desire for infamy, copycat study of other shooters, past domestic violence, narcissism and access to firearms.

Washington Post