Mass shootings and mental illness

Portside - An FBI study that monitored pre-attack behaviors of mass shooters between 2000 and 2013 found that 25% of them had diagnosed mental illnesses (which includes non-psychotic conditions, such as depression and substance abuse). This is not far off from the 23% of US adults who experienced mental illness in 2021, according to the National Alliance on Mental Illness. Only 5% of the shooters in the FBI study had been diagnosed with a psychotic disorder. And a diagnosis doesn’t necessarily assert a causal relationship. In most cases, the relationship between the violent act and mental illness is incidental (Columbia Psychiatry, 7/6/22).

In a piece for the American Association of Medical Colleges (1/26/23), John Rozel and Jeffrey Swanson cited a 2018 study that found that less than 5% of mass shooters had any record of a gun-disqualifying mental health adjudication, like involuntary hospitalization: Indeed, if serious mental illnesses suddenly disappeared, violence would decrease by only about 4%. More than 90% of violent incidents, including homicides, would still occur.