Prisons now house three times more people with serious mental illness such as schizophrenia, bipolar disorder and major depression than mental health hospitals. The federal Bureau of Justice Statistics says half of state prisoners nationwide have a mental health problem. In Massachusetts, there will likely be a victory in a lawsuit filed last week against the Department of Corrections challenging its practice of placing mentally ill inmates in solitary confinement. The evidence is overwhelming that it is cruel and a violation of basic human dignity to force prisoners with serious mental illness to spend years confined round the clock in claustrophobic cells, with nothing to do, and no one with whom to have a normal conversation.

In Massachusetts, there will likely be a similar victory in the lawsuit filed last week against the Department of Corrections. The evidence is overwhelming that it is cruel and a violation of basic human dignity to force prisoners with serious mental illness to spend years confined round the clock in claustrophobic cells, with nothing to do, and no one with whom to have a normal conversation. The cruelty is compounded because mental health services for segregated prisoners typically consist of nothing more than medication and brief periodic cell-front checks-ins.

Prisoners with serious mental illness need structured days and interaction with others. They need group therapy, individual counseling, training in daily living, education about their illness, supervised recreation and other forms of psychiatric rehabilitation as well as medication. Yet as is often the case in prison, security and punishment trump mental health needs.

Untreated or undertreated, the mentally ill in segregation may deteriorate. They may rant and rave, babble incoherently or huddle silently. They may talk to invisible friends and live in worlds constructed of hallucinations. They may beat their heads against walls, yell endlessly, cover themselves with feces and self-mutilate until their bodies are riddled with scars. Many try suicide; some succeed.

Why are there mentally ill prisoners in segregation? Because prisons have become the nation’s mental health facilities.

Prisons now house three times more people with serious mental illness such as schizophrenia, bipolar disorder and major depression than mental health hospitals. The federal Bureau of Justice Statistics says half of state prisoners nationwide have a mental health problem.

They end up in prison because the community mental health systems are in shambles - fragmented, underfunded and unable to serve the poor, the homeless and those who are substance-addicted as well as mentally ill.

Nationwide, half of the state inmates with mental health problems were convicted of nonviolent offenses, primarily low-level drug and property offenses. Alternatives to incarceration may have been appropriate, but the court’s hands are tied by mandatory sentencing laws.

Once behind bars, the mentally ill find themselves ill-equipped to handle the stresses and rules - formal and informal - of prison life. They are more likely to be victimized and more likely to be injured in a fight than other inmates. They are more likely to break the rules. They are more likely to behave in ways that annoy, disgust and even enrage security staff who have scant training in how to recognize, much less cope with, symptoms of mental illness.

Moreover, prison mental health services across the country are woefully deficient, crippled by understaffing, insufficient facilities and limited programs, and swamped by the sheer number of prisoners who need them. Lacking resources and options, prison officials put problem prisoners, including the mentally ill, in segregation, where by virtue of being locked up around the clock they cause less trouble.

States can institute policies to keep mentally ill inmates out of segregation or wait for litigation to force them to do so. They can improve the quantity and quality of mental health services they provide. But even those necessary steps fail to confront the larger question - should prisons be de facto mental institutions? If not, then the country must reduce the number of mentally ill people who are incarcerated.

The starting point is to reform needlessly harsh and counter-productive sentencing laws. States must also increase the scope and effectiveness of community mental health systems. The mentally ill do not have to end up in prison, but first elected officials must show far more compassion and common sense than they have to date.