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What Really Happens Inside Prisoner Isolation Cells?

Research reviews the traumatic impacts of solitary confinement.

Source: Donald Tong/Pexels
Source: Donald Tong/Pexels

Prison architecture has historically featured designs that function to minimize contact between inmates as punishment for criminal activity. There is little evidence for the rehabilitative value of isolation, however, ample evidence points to a slew of mental health issues that come from being socially and physically cut off for long periods of time. Researchers recently reviewed the threats to mental health posed by prison confinement and, more generally, risk factors associated with living in physical spaces that promote social detachment. Among them are hypersensitivity to external stimuli, hallucinations, anxiety, panic attacks, memory deficiencies, concentration issues, paranoia,m and impulse control.

Solitary Confinement

Solitary confinement is currently used in criminal justice systems worldwide as a means to manage disruptive inmates. Generally speaking, the method involves placing an inmate in a secluded cell with little or no social interaction. Time requirements for solitary confinement, or disciplinary segregation, in federal prisons are defined by the severity of the inmate offense classified into one of four categories ranging from “low, moderate, high, greatest.” For the high and greatest categories, disciplinary segregation can last 30-60 days.

Mental Health Outcomes

Emphasizing the stark reality of isolation, Breslow (2014) described solitary confinement as a “prison within a prison.” Inmates facing punishment for transgressions committed on other inmates are often relocated to solitary confinement cells ordinarily found within the Special Housing Unit (SHU) of a prison—colloquially referred to in the United States as “hotbox”, “hole”, “punk city”, “lockdown”, and “SCU” (Solitary Confinement Unit). Here the inmates are housed in a tiny cell, normally about the size of a horse stable (ranging from 6 feet by 9 feet to 8 feet by 10 feet). Food is presented exclusively through a small door slot in to a room that includes a bed, sink, toilet, and usually no window. Customarily, a single hour of exercise makes up the entire allotment of time spent outside of solitary confinement. For the remaining 23 hours, they are left inside, without human contact of any kind.

Typically, a trip to the SHU (referred to by many as “the shoe”) occurs for one of the following three reasons. (1) Multiple referrals for misbehavior can result in a sentence of solitary confinement. (2) Prison officials may place an inmate in the SHU for his own protection. It is not unusual to find inmates motivated to inflict harm on others, especially in the high profile cases where the newly arriving prisoner has crossed the line even by hardened criminal standards. The SHU thus serves a preventative function by placing the inmate out of danger for some period of time. (3) The least common path to solitary is through a court order. In these cases, a judge would outline specific reasons why the sentence of solitary confinement is a requirement. Here we summarize some of the factors associated with extended periods of isolation.


Does solitary confinement have long term negative consequences? If so, what is the evidence and what are some of the implications for mental health and psychological functioning? In one of the first modern SHU experiments, Walters, Callagan, and Newman (1963) compared a group of prisoners in solitary for four days to a non-solitary group also over a four day period. Results indicate that anxiety increased for the solitary group, but not the others. Although no psychomotor deficits were found, it is remarkable that changes to anxiety levels were documented in this short amount of time.


Bauer and colleagues (1993) showed that prisoners who experienced long-term solitary confinement had increased symptoms of depression, anxiety, increased arousal, and vegetative complaints. The researchers examined former political prisoners diagnosed with various psychiatric conditions using the Diagnostic and Statistical Manual of Mental Disorders (DSM). Out of the 55 prisoners in the study, 35 experienced long-term effects that did not improve even through an extended period of time (Bauer, Priebe, Blaring, & Adamczak, 1993).


Within the prison population of the United States, the leading cause of death is suicide and the risk factor most closely linked to it is depression. According to Kaba, et al. (2014), the combination of solitary confinement and having a diagnosable mental illness greatly increases the probability of committing serious self-injury. In a data set of over 240,000 inmate medical records from 2010 to 2013, the researchers found that 53% of the acts of self-harm came from individuals in solitary confinement. This is noteworthy because only 1,303 inmates out of the 240,000 were in isolation, yet more than half of the self-injuries came from this group.

Aggression and Impulse Control

Violence direct at self and others is seen as disobedient behavior and the punishment for acting aggressively is often more time in solitary confinement (Grassian, 2006). Some inmates are so desperate for interaction that they will go to behavioral extremes. Facing pepper spray or a taser gun because of uncontrolled screaming or overflowing a toilet can be seen, in this context, as positive attention especially when the alternative is no human contact at all. Extremely limited social interaction combined with lack of sunlight creates the perfect conditions for this type of behavior to develop (Arriago, et al., 2007).

Final Note

This list of mental health outcomes underscores the message, meaningful to behavioral scientists and therapists, that solitary confinement, although widely practiced, is an excessive punishment that lacks any true rehabilitative purpose. Locking people away for 22 or more hours a day is so egregious that a 2011 United Nations special report condemned the practice in general and specifically banned the practice for juveniles and the mentally ill.


Anderson, G. (2010) Loneliness among older adults: A national survey of adults 45+. American Association of Retired Persons.

Arrigo, B. A., & Bullock, J. L. (2007). The psychological effects of solitary confinement on prisoners in supermax units: Reviewing what we know and recommending what should change. International Journal of Offender Therapy and Comparative Criminology, 52(6), 622-640. doi:10.1177/0306624x07309720

Bauer, M., Priebe, S., Blaring, B., & Adamczak, K. (1993). Long-term mental sequelae of political imprisonment in East Germany. The Journal of Nervous and Mental Disease, 181(4), 257-262. doi:10.1097/00005053-199304000-00007

Bennett, K. (2017). Adaptive function of aggression. In Zeigler-Hill, V., & Shackelford, T.K. (eds.), Encyclopedia of Personality and Individual Differences. (pp.1-3). Springer International Publishing AG.

Breslow, J. M. (2014, April 22). FRONTLINE. Retrieved December 12, 2016, from…

Grassian, S. (2006). Psychiatric effects of solitary confinement. Washington University Journal of Law Policy 22, 325-384.

Kaba, F., Lewis, A., Glowa-Kollisch, S., Hadler, J., Lee, D., Alper, H., Selling, D., MacDonald, R., Solimo, A., Parsons, A., & Venters, H. (2014). Solitary confinement and risk of self-harm among jail inmates. American Journal of Public Health, 104(3), 442.

Kane, T.R. (2011). Inmate discipline program. U.S. Department of Justice, Federal Bureau of Prisons.

Walters, R. H., Callagan, J. E., & Newman, A. F. (1963). Effect of solitary confinement on prisoners. American Journal of Psychiatry, 119(8), 771-773. doi:10.1176/ajp.119.8.771

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