Last month the Supreme Court rightly blocked the execution of Scott Panetti, a Texas man who was convicted of a double murder and who suffers from delusional schizophrenia. The case drew public attention to the intersection between mental illnesses and executions.

But what about those who are mentally ill and imprisoned, but not on death row? A national conversation on this issue is urgently needed.

There is a pervasive attitude that such people are getting what they deserve: After all, like Panetti, they are in jail for something.

But did you know that the Los Angeles County Jail houses the largest psychiatric population in the country? That's not justice. That's emblematic of a national emergency.

Before the 1960s, people with mental illnesses were generally cared for in institutional settings, mostly state-run psychiatric facilities. Many advocates rightfully saw this as "warehousing" people who could be cared for in less restrictive settings. Federal legislation and the courts powered a move toward deinstitutionalization, calling on states and counties to provide resources for social services, vocational rehabilitation and treatment services. The introduction of effective antipsychotic medications also drove the trend toward deinstitutionalization.

In the decades since, community-based services have helped many people. But the situation today constitutes a national failure.

What's gone wrong?

Most important, the necessary community resources didn't materialize in anywhere near the level that was needed. Also, antipsychotic medications, while powerful treatments, don't work in isolation. Patients need a relationship with a psychiatrist, clinic or other stabilizing force to ensure adherence to drug regimens and achieve the best possible recovery.

Deinstitutionalization has succeeded in decreasing the overall number of hospital beds, but an unforeseen consequence has been the proportional increase in the number of people with mental illnesses housed in the criminal justice system. Worse, once imprisoned, people with mental illness are shown to have much longer incarcerations than other inmates, primarily because a prison environment and lack of treatment aggravate the very illness that has led to their objectionable or antisocial behavior.

While no one would argue that Panetti belongs on the streets, his case compels us to consider the justice system's role: Is it to mete out punishment that seeks retribution, or are there cases where real justice means effective treatment that seeks rehabilitation?

Consider again Los Angeles County: In 2002 there were 38,600 psychiatric evaluations at the inmate reception center of the Twin Towers jail. Of these, 23,190 people (60 percent) were found to be in need of mental health treatment. A reasonable person could not fail to see the correlation between decreased funding for mental health resources, the closure of hospital beds, homelessness and the criminalization of mental illnesses. Untreated and lacking access to long-term care, people with mental illnesses often end up with symptoms and behaviors that result in jail time.

Cuts in state Medicaid budgets promise to exacerbate these problems. Not only is this shift in funding a blight on our society, it also costs money — a lot of money. Corrections officials, mental health workers, medication, amortization of buildings and time spent by police in court all cost more than treating patients appropriately in their community. This doesn't make financial sense, much less humanitarian sense.

When considering the direction of public policies that affect those with mental illnesses, politicians and other officials must be guided by the latest research.

Government-funded studies have shown in recent years that jail-diversion programs, which help people get the treatment they need, result in positive outcomes for individuals, communities and the criminal justice system. While jail diversion does generally result in lower criminal-justice costs and greater treatment costs, studies are underway to analyze the differential.

The question the court answered in the Panetti case was about one's fitness to be executed, but in many more cases, the question is about the appropriateness of incarceration at all.

Marcia Kraft Goin is a past president of the American Psychiatric Association and director of residency training in the Psychiatric Outpatient Department at Los Angeles County General Hospital/University of Southern California School of Medicine. She wrote this commentary for the Washington Post.