Homelessness is the cause of mental illness and addiction, not the other way around, say Democrats. “Only one in seven people who becomes homeless has a mental health problem,” said California gubernatorial candidate Tom Steyer in a forum with Ezra Klein, “But virtually everyone who stays on the street for a long time develops one.” Klein agreed that the main issue was economic. “Before people become homeless, they are housed,” he said, “and what tends to happen is that they have an income sh...