There are nearly 100,000 people being held in solitary confinement today in America’s prisons. They are locked up in cramped, often windowless cells for nearly 24 hours a day. They eat alone. They exercise alone in small fenced-in areas known as cages or dog runs. They are almost completely segregated from the mainstream population and there are no programs available to them. Most aren’t allowed to make phone calls to loved ones. And they are often subject to extreme and excessive punishment, euphemistically called “cell extractions.” Robert Hillary King, an Angola 3 member who spent 29 years in solitary confinement, has called this isolation a matter of “moral depravity.”

Forensic psychiatrist Terry Allen Kupers knows this moral depravity all too well. He has spent 40 years evaluating prisons and jails and testifying in class action suits revolving around prisoners’ rights issues such as overcrowding, sexual abuse and the lack of decent mental health treatment.

In his new book, “Solitary: The Inside Story of Supermax Isolation and How We Can Abolish It,” Kupers describes how long-term solitary confinement destroys the minds of those imprisoned. He also explains how prisons became warehouses for the mentally ill, which set the stage for a 30-year boom in supermax prison construction and the placement of a large number of prisoners in solitary confinement.

Here, in his first extensive interview since the September release of “Solitary,” Kupers discusses private prison practices, the role of race in solitary confinement and why he does this painful work.

Describe what you look for when you investigate a prison.

I tour the facilities, noting things like crowding, gymnasiums converted into impromptu dorms, prisoners lying in their bunks in the middle of the day because there is nothing productive to do, excessive use of force [by guards] and filthy isolation cells. I talk to prisoners about the conditions and their medical and psychiatric treatment. I review cartons of documents, including prison policies, medical charts and reports of audits and accreditation inspections. I would like to talk to staff in depth about what they do, but usually the attorney general will not permit that. I have to learn the staff’s perspective by reading depositions they give in the case.

What role do you play in court cases?

I am a psychiatric expert witness, or sometimes I serve as monitor after the case is settled and I assess the state’s performance in carrying out the court’s orders. I testify about inhumane and unconstitutional conditions of confinement, including solitary confinement, inadequate or harmful mental health services and sexual abuse. After I have done my investigation, the county or state’s attorneys depose me under oath. Some large class actions are settled at that point. Some go to trial, and then I testify in court as a psychiatric expert. After I describe unconstitutional and abusive conditions and practices, I am asked what remedies I would recommend, and that’s when I have an opportunity to share with the judge or jury the proven effective alternatives to prison crowding and solitary confinement.

How do private prisons play into all this?

Private prisons are the sites of some of the worst human rights abuses. After all, the way corporations make a profit is to cut corners on staffing costs and drastically cut down on rehabilitative programs. Private prisons, which tend to be more crowded than those run by the government, rely a lot on solitary confinement to manage prisoners. They pay staff lower wages and provide them less training than in government facilities. President Obama favored moving away from private prisons and solitary confinement in the federal system, but the Trump administration favors the private prison corporations, especially in the realm of immigration detention. The stock of the private prison corporations rose precipitously in value immediately after Trump won the election.

What motivated you to get involved in prison work?

Back in the day, I was the physician for the Black Panther Party’s Bunchy Carter Free Clinic in South Central L.A. In 1971, COINTELPRO and the LAPD Red Squad attacked the Panther office—the building where the clinic was located—and shot the 13 Panthers sleeping there. I went to the L.A. County Jail Hospital Ward and demanded to see my patients. The conditions and treatment in the jail were horrid, and I reported that to the press.

How did you end up testifying in class action cases?

A couple of years later, the ACLU sued the L.A. County sheriff over unconstitutional conditions and inadequate treatment at Men’s Central Jail and asked me to be their expert witness. I went back in and this time reported the appalling conditions to the federal judge. The psychiatric community was just beginning to discover that a large number of individuals suffering from serious mental illness were behind bars. Once I learned of the horrors that regularly occur [in jails and prisons] I felt compelled to investigate, testify and generally holler about the massive abuses.

I understand there are 100,000 prisoners in solitary confinement today. How did that happen?

In the 1980s, prisons were overcrowded [due to] longer sentences and the War on Drugs, and they were out of control with a lot of violence. The choice was to either downsize the prison population through sentencing reform while upgrading rehabilitation for prisoners, or to lock up “the worst of the worst” in solitary. The powers that be decided on [the isolation option]. This was a historic wrong turn, and we entered the age of supermax. There was no improvement in the violence or gang problems, but there was massive human damage.

What role does race play in solitary confinement?

It’s all about race, of course. It starts with who goes to prison: While approximately 13 percent of the U.S. population is African American, over 40 percent of prisoners are Black. Latinos are equivalently overrepresented in prison. In terms of consignment to SHU (Security Housing Units), there is an unfortunate national trend to send White prisoners to mental-health treatment for the same rule-breaking behaviors that get Blacks placed in SHU.

Can you given me an example?

In New York, according to a 2014 study by the New York Advisory Committee to The U.S. Commission on Civil Rights, African Americans make up almost 18 percent of the state population but nearly 50 percent of the state’s prisoners and 59 percent of those kept in extreme isolation. For prisoners under age 21, Black youths constitute 66 percent of those in solitary confinement.

In other words, the racial disparities and discrimination that permeate our society are multiplied and exaggerated behind bars. The racial discrimination of officers is well known, and that includes corrections officers.

Why are there so many people with serious mental illness in our jails and prisons, and why do so many of them wind up in solitary confinement?

With deinstitutionalization, the War on Drugs and the de-funding of social welfare safety net programs, a lot of people with mental illness ran afoul of the law. In prison, they are victimized or they find it difficult to follow all the rules and they get singled out for punishment with solitary confinement. Just about everyone in solitary develops dreadful symptoms, including massive anxiety, mounting anger, despair, paranoia, repetitive behaviors such as pacing, and, too often, suicide. When individuals suffering from mental illness are consigned to SHU, it exacerbates their mental health problems. They develop worse disabilities and prognoses.

What effect is the Trump/Sessions regime having on prison reform, and, by extension, solitary confinement?

Before Trump, there was a bipartisan effort to put radical sentence reform on the legislative agenda. Obama, [Supreme Court Justice Anthony Kennedy] and many influential people were calling for a move away from solitary confinement, and we were on a path to reform. But Attorney General Jeff Sessions insists on the harshest sentences and Trump likes waterboarding. I worry that the progress of recent years will be reversed. The scenario that scares me the most is the detention of millions of immigrants in [Immigration and Customs Enforcement] detention centers, where the feds ask the states and counties to incarcerate the overflow and prison crowding returns with a vengeance. Correctional authorities [will] once again make the wrong decision and put a lot of prisoners in solitary.

I imagine that the correctional authorities insist they need solitary confinement to keep prisons safe. How do you respond to that?

Research shows no improvement in the violence rate in prisons, the gang problem continues unabated, and a huge number of prisoners are very damaged from their stints in solitary. Actually, prisoners who spend time in solitary are more difficult to manage after they are returned to general population, and that’s why the violence rate is not improved.

Tell me about some of the court cases you’ve been involved with.

I have testified in dozens of court cases. Among the most significant is Coleman v. Wilson, which was about mental healthcare throughout the California Department of Corrections and Rehabilitation. This case resulted in an order from the Supreme Court to downsize the state’s prisons. Then there was Presley v. Epps, which was about conditions and inadequate treatment for prisoners with serious mental illness at the supermax unit within the Mississippi State Penitentiary at Parchman. And Ashker v. Brown was a case that came out of hunger strikes at Pelican Bay State Prison in California. It addressed conditions and due process in the SHU.

Do you think class action lawsuits an effective way to reform the criminal justice system? What about legislation and social activism? What is needed at this point?

Lawsuits alone will not change things, but they permit us to enter the prisons and assess the damage. Only with social activism, starting with calls for radical sentence reform and massive downsizing of the prisons, will we see progress. Some legislatures are responding to advocates, including prisoners’ families, and they’re passing sentencing- and prison-reform legislation.