After a series of deadly mass shootings in the United States, the National Rifle Association and some Republican leaders and conservatives are pointing to mental illness. This approach raises a question: How can the mental health system stop gun violence when mental illness is so rarely the cause of it? We revisit a conversation from 2018 with a psychiatrist who is wrestling with that challenge. Guest: Dr. Amy Barnhorst, the vice chairwoman of community psychiatry at the University of California, Davis.