Security Housing Unit

Solitary confinement is a form of imprisonment in which an inmate is isolated from any human contact, often with the exception of members of prison staff, for 22–24 hours a day, with a sentence ranging from days to decades. It is mostly employed as a form of punishment beyond incarceration for a prisoner, usually for violations of prison regulations. However, it is also used as an additional measure of protection for vulnerable inmates. In the case of prisoners at high risk of suicide, it can be used to prevent access to items that could allow the prisoner to self-harm.

Solitary confinement is colloquially referred to in American English as "the hotbox", "the hole", the BOX, the Bing, "lockdown", HDM (Housing Detention for Men), "AdSeg" (administrative segregation), the "SHU" (pronounced "shoe"), an acronym for "Special Housing Unit" or "Security Housing Unit", or "the pound"; in British English as "the block", "The Segregation Unit", or "the cooler". It has also been called prison "'segregation' and 'restrictive housing.'"

Solitary confinement receives severe criticism for having detrimental psychological effects and constituting torture.

Research surrounding the possible psychological and physiological effects of solitary confinement dates back to the 1830s. When the new prison discipline of separate confinement was introduced at the Eastern State Penitentiary in Philadelphia in 1829, commentators attributed the high rates of mental breakdown to the system of isolating prisoners in their cells. Charles Dickens, who visited the Philadelphia Penitentiary during his travels to America, described the "slow and daily tampering with the mysteries of the brain to be immeasurably worse than any torture of the body". Prison records from the Denmark institute in 1870 to 1920 indicate that staff noticed inmates were exhibiting signs of mental illnesses while in isolation, revealing that the persistent problem has been around for decades.

The first comment by the Supreme Court of the United States about solitary confinement's effect on prisoner mental status was made in 1890 (In re Medley 134 U.S. 160). In it the court found that the use of solitary confinement produced reduced mental and physical capabilities. The use of solitary confinement in prisons was first introduced to regulate unruly prisoners and keep them away from the rest of the prison society (Haney, Craig; Lynch, Mona). However, solitary confinement has been linked to several developments of mental disorders, one of which being Ganser syndrome. A man developed Ganser syndrome after being held in solitary confinement for a long term sentence; however, that development is seen as rare and is unlikely in most cases.

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