Housing the mentally ill is no more expensive than leaving them on the street, concludes a study by researchers from the University of Pennsylvania, published in the current issue of Housing Policy Debate. "A considerable amount of public dollars is spent essentially maintaining people in a state of homelessness," lead author Dennis Culhane says.

For two years, the study tracked nearly 5,000 homeless people suffering from severe mental illness in New York City. The scientists relied on official records to analyze how often these subjects wound up in a prison, hospital or shelter. Approximately half the subjects later received supportive housing beginning in 1993 under the NY/NY agreement, a public initiative of the State and City of New York. And for another two years, the researchers examined the impact of this placement. They found that it cost the same amount of money in public fundsnamely $40,500 a yearto house a mentally ill homeless person as it did to leave them on the street, where they rely more on social services.

"What this study proves is that by putting those same dollars into supportive housing, the solution can pay for itself," Culhane says. He notes that $40,500 a year covers housing as well as comprehensive health support and employment services. "Policymakers could substantially reduce homelessness," he concludes, "for a large and visible segment of the homeless population, often thought to be stubbornly beyond the reach of the social-welfare safety net, at no or marginal cost to the public."