Violence gauge

Regarding the mass shooting in Las Vegas, letter to the editor (“Mental illness,” Page A33, Oct. 8), ended with this question: “... is there any way to predict or control this kind of violent behavior?” Unfortunately, at the present time, the answer is no. Psychiatrists and psychologists are notoriously terrible at predicting who, among patients discharged from mental hospitals, is going to commit a violent act. The best predictors it turns out, are prior violent behavior and a diagnosis of psychosis. And even then, the rate of success in predicting violence is very poor.

Only a small percentage of people with even the most severe forms of mental illness are violent. Stephen Paddock’s girlfriend described him as a kind and caring man; his family said he had no history of violence, and there seems to be no evidence to the contrary. Even if he is found to have had some psychological problems, such as depression, that in itself would not predict violence. The idea that society is somehow going to solve the violence problem by focusing on the mentally ill is pure fantasy. There is no cure for psychosis. And besides, people who are violent are not necessarily mentally ill.

What we can use to help predict who is likely to be violent is who has purchased the means to commit mass murder — who has purchased an automatic or semiautomatic firearm or who has purchased bomb-making equipment. People can still purchase large amounts of ammonium nitrate fertilizer even after Timothy McVey blew up the Murrah building in Oklahoma City, killing 168 people, and people can amass a huge store of weapons, such as Stephen Paddock, without anyone’s knowing. If the ATF and FBI had known he was amassing an arsenal of weapons, perhaps this massacre could have been averted. Sarah A. Burnett, Houston