It took Allegheny County President Judge Joseph James 30 years to prove his hunch was right: It is less expensive to treat mentally ill criminals involved in minor crimes than it is to jail them.

An independent study of the Allegheny County Mental Health Court, started in 2001, found that not only does treatment help the participants, it also saves money.

The study released yesterday by the Rand Corp. showed that the increased cost of treating mentally ill people who were criminally charged was offset by the decrease in jail costs.

The Allegheny County Mental Health Court works by steering people, who are committing crimes mostly because they are mentally ill, into treatment instead of jail. The court then uses intensive probation to make sure the defendants are sticking to their treatment plans so they can stay out of jail.

John B. Engberg, an economist for Rand and one of the study's authors, said over a two-year period, just for the 200 people who were in the court, there was a savings of about $3.6 million.

"What we have here is proof that it worked," Estelle Richmond, secretary of the state Department of Public Welfare said. "It does save money and it does help people get better."

Judge James said that's what he figured when he worked for the district attorney's office and began prosecuting cases with defendants who obviously had mental health problems.

"It has to be cheaper to treat these people than arresting them, releasing them and arresting them again," he recalled thinking.

Ms. Richmond said she wants to use Allegheny County's Mental Health Court as a model in counties across the state. Currently only York and Erie counties have similar courts and another is starting in Lackawanna County.

Marc Cherna, director of the Allegheny County Department of Human Services, said the program also improves public safety by preventing crimes.

Amy Kroll, director of forensic services in the Department of Human Services, said the recidivism rate for the 500 offenders who went through Mental Health Court is 14 percent. While she had no figures for the rate for mentally ill people nationally, she said the overall rate of recidivism is about 67 percent.

"If you can help people and they don't [commit more crimes], everybody is safer," Mr. Cherna said.