MANY OF THE mentally ill prisoners in Massachusetts live in conditions that evoke an 18th century madhouse. Even people who believe that prisons exist solely for punishment should not abide a system that forces prisoners with diagnosable mental illnesses to spend 23 hours a day in solitary confinement, where they grow crazier, more desperate, and more dangerous by the day.

A three-part Globe Spotlight series that began yesterday plumbs the decisions and conditions that led to 15 suicides in state prisons since 2005 - triple the average rate in other states. Some cases may be linked to sadistic treatment by guards. But of the suicide deaths, and the more than 3,000 suicide attempts and self-inflicted injuries in the past decade, most resulted from a deadly pattern of sloppy communication, poorly-trained officers, and hardbitten attitudes about the needs of sick inmates. The mentally ill now make up about one-quarter of the state's 11,000 prisoners.

The Spotlight report provides new and disturbing details about the lives and deaths of suicidal prisoners. But the overarching problem has been well documented by special prison commissions dating back to 2000. With each report, Department of Corrections officials embrace the recommendations and promise more enlightened treatment. But nothing changes for the prisoners in the notorious 10-Block at MCI-Cedar Junction and other dead-ends of the prison system.

Now the Disability Law Center is suing DOC in federal court. It demands the construction of residential treatment centers in the system's maximum-security prisons, where none now exist. The DOC says that 60 such beds will come on line soon at the maximum-security prison in Shirley. A new behavior management unit is also planned for Cedar Junction in Walpole. But similar promises have been made before. The best way to ensure that improvements actually happen is for the state to settle the lawsuit, which sensibly calls for 15 hours per week of therapy and rehabilitation for mentally ill prisoners.

The state Department of Mental Health reviews medical records in several DOC facilities. But it should be given direct oversight of treatment programs as well. Private contractors who supply mental health services for the prison need to answer to medical professionals, not public safety officials as is now the case. Privatization has not succeeded in this field. If DMH can't provide direct services, then it should at least provide more oversight.

There are legislative remedies, as well. State representatives Ruth Balser and Kay Khan have sponsored important legislation to elevate the treatment standards for prisoners and training requirements for correctional officers. But so far, the bills have languished.

Like it or not, the prisons are de facto mental institutions. They can't be run like ancient dungeons.

© Copyright 2008 Globe Newspaper Company.