UC Santa Cruz psychology professor Craig Haney, the nation's leading expert on inmate mental health, told a U.S. Senate subcommittee Tuesday that, for many inmates, "solitary confinement precipitates a descent into madness."

Prisoners in long-term solitary confinement suffer psychological breakdowns from the lack of human contact that can lead to psychosis, mutilations, and suicide, Haney told senators on the Senate Judiciary Subcommittee on the Constitution, Civil Rights, and Human Rights.

The dramatic increase in solitary confinement in the U.S. since the late 1970s is the result of "the confluence of three unfortunate trends" – the era of mass imprisonment, the shift in responsibility for housing the mentally ill to the nation’s prison systems, and the abandonment of the notion of rehabilitation, wrote Haney, chair of UCSC's Legal Studies program. An estimated 80,000 of the 2.3 million inmates in U.S. prisons and jails are in long-term solitary confinement. 

"Solitary confinement doesn't drive everyone crazy but we do know that time spent in these places is often more than merely painful," Haney said, "moving beyond suffering to placing prisoners at grave risk of psychological harm."

Subcommittee chairman Sen. Dick Durbin, D- Ill. invited Haney and five others to testify at the first-ever hearing on the constitutional, fiscal, and public safety consequences of solitary confinement. Dozen of others interested in testifying submitted written remarks.

"Professor Haney, we couldn't have done this without you," Durbin told Haney. "I mean, you've done such amazing research in this area."

As a graduate student in 1971, Haney was one of the principal researchers in a widely publicized study that became known as the “Stanford Prison Experiment.” He and his colleagues placed a carefully screened group of psychologically healthy college students in a prison-like environment, randomly assigning half to be guards, half prisoners.

They halted the experiment when they observed that the behavior of the otherwise psychologically healthy volunteers in the simulated prison rapidly deteriorated into mistreatment and emotional breakdowns.

Since then, Haney has conducted groundbreaking research into the effects of incarceration, solitary confinement, and capital punishment. His research and analysis was cited several times last year in the majority opinion when the U.S. Supreme Court upheld a  ruling ordering California to release 46,000 prisoners to relieve overcrowding.

Haney, who toured several California prisons to assess overcrowding and staffing, testified that prison mental health workers are too overburdened to provide adequate care to inmates, which not only harms prisoners but also endangers the public once those prisoners are released.

"We put far too many people in prison, we pay far too little attention to what happens to them while they're there, we keep them there for far too long, then we disregard what happens to them when they try to make the difficult transition to come out into the free world," he said.

In April, Haney was appointed to a National Academy of Sciences panel to study the causes and consequences of high rates of incarceration in the U.S.

Also testifying Tuesday, were the director of the Federal Bureau of Prisons, the commissioner of the Mississippi Department of Corrections, and Anthony Graves, who was released from Texas death row in 2010 after 18 1/2 years, 10 of them in solitary confinement for a crime he did not commit.