In 1969, Robert King was arrested for a crime he did not commit, convicted, and sent to Louisiana State Penitentiary. Three years later, another inmate was stabbed to death, and the prison authorities pinned the murder on King. His conviction was eventually quashed, and King was set free, but only after spending 29 years in solitary confinement.
"I became acclimated to short distances," says King. "Within 6 months I became almost totally blind, and I had to retrain my eyes by looking into the distance. Now, my geography is completely messed up. I get confused if I have go four or five blocks, even if I know exactly where I am."
King spoke during the annual meeting of the American Association for the Advancement of Science in Chicago last month, joining a panel of academics to discuss the psychological effects of solitary confinement.
Large-scale use of solitary confinement came about in the 19th century, together with the rise of modern penitentiary systems, said Peter Scharff Smith, research director of the Danish Institute for Human Rights. The rationale was rehabilitation through isolation-essentially, to keep the offender away from the corrupting influence of other prisoners. During this time period, hundreds of thousands of people were housed in solitary confinement, amounting to what Smith called "a grand psychological experiment."
It quickly became apparent that isolating prisoners could be psychologically damaging. For example, the governor of one Danish prison, opened in 1859, condemned the practice, warning that it "represents a significant danger to prisoners' mental health." In 1890, the US Supreme Court noted that "considerable numbers of prisoners fell, even after short confinement, into a semi-fatuous condition from which it was next to impossible to rouse them. Others became violently insane, and others still committed suicide."
Nevertheless, solitary confinement was used widely well into the 1930s. Starting in the 1960s, following reports that Chinese prisoners been isolated and "brainwashed" during the Korean war, the CIA took an interest in using solitary confinement as a method of interrogation, and also conducted experiments into the effects of sensory deprivation. "Solitary confinement can be used to deprive the subject of many of the sights, sounds, tastes, smells and tactile sensations to which he has grown accustomed," stated the CIA Counter-Intelligence Interrogation Manual of 1963, adding that "the interrogator can use this coercively."
Today, solitary confinement is still used in many prisons around the world, in various ways and for different reasons: as a preventive tool for managing violent prisoners; as a form of punishment; as a way of isolating prisoners during ongoing criminal investigations; and voluntarily, as protection from other prisoners. In the US, use of the practice began to increase again in the 1980s, along with an increase in the number of super-maximum security ("supermax") prisons. According to statistics compiled by the Commission on Safety and Abuse in America's Prisons, its use has continued to increase ever since; today, more than 80,000 people are being held in solitary confinement.
Craig Haney, a professor of psychology at the University of California, Santa Cruz, has been studying the psychological impact of solitary confinement for nearly 20 years, and has interviewed more than 500 prisoners, all of whom have been subjected to isolation for prolonged periods of time.
"Prisoners live in an 80 square foot cell-a bit bigger than a king-size bed-and they eat, sleep and defecate in this environment," said Haney. Prisoners held under such conditions spend at least 22 hours per day locked in their windowless cells, and can go months, years or even decades without coming into contact with other people or the outside world. "The US is an outlier in the extent to which we use isolation and solitary confinement on a long-term basis."
According to Haney's analyses of the interviews he has conducted, prisoners held in solitary confinement are at far higher risk than the general prison population of having severe stress, chronic depression, and suicidal thoughts. Because our sense of self is defined in large part by our interactions with others, many also experience a loss of personal identity, he said.
Neurobiologist Huda Akil of the University of Michigan pointed out that, while there have been no direct neurological studies of the effects of solitary confinement, the history of sensory deprivation research, together with more recent animal studies, strongly suggests the practice is hugely detrimental to both mental and physical health.
Akil referred to a large body of evidence into the effects of environmental impoverishment. We've known since the pioneering work of David Hubel and Torsten Wiesel that the developing brain depends strongly upon sensory stimulation, and many studies since then have shown that it continues to depend on it throughout life. Keeping experimental animals in impoverished environments dramatically reduces the density of synaptic connections in the brain, whereas environmental enrichment has the opposite effect.
Akil pointed out other possible effects of solitary confinement. Research in humans shows that depression is associated with a disruption of circadian rhythms; research published in the past few years suggests that this is associated with an increased risk of Alzheimer's disease and other neurodegenerative conditions. Depression is also associated with a reduction of hippocampal volume, a brain structure that is critical for memory and spatial navigation. This might explain why King has trouble finding his way around.
Akil went on to describe some of her own work, showing that levels of a protein called Fibroblast Growth Factor-2 (FGF2) are significantly reduced in anxiety and depression. FGF2 and related proteins are also involved in synaptic plasticity, the process by which connections between nerve cells are strengthened, or created anew, in response to experience. "FGF is important for remodeling the brain and creating new connections between cells," says Akil. "A decrease in FGF2 and other growth factors impoverishes the brain."
Akil and the other panelists all agreed that the practice of solitary confinement is the equivalent of torture: It is cruel, inhumane and-given that the vast majority of US prisoners held in isolation are there not because of violent behavior, but because of alleged affiliations with street gangs-completely unnecessary.
"To me, the behavioral data are compelling, but it'll take more evidence at the brain level to really get the point across," said Akil, adding that ethical guidelines forbid researchers from keeping animals in social isolation for long periods of time. "There is no question that we do better by our mice and rats [than by our prisoners]."