In the United States, solitary confinement used as a form of incarceration drastically increased in the 1980s. The increase was due in large part to an attempt to control prisoners and reduce violence in overcrowded prisons. Supermax or super-maximum security prisons rely heavily on solitary confinement to house and punish the most dangerous criminals. However, solitary confinement of over 15 days adversely affects mental health in prisoners and it has not been shown to have an effect on levels of prisoner violence or recidivism rates. The practice also violates the UN Convention on Torture and Other Cruel, Inhuman, and Degrading Treatment or Punishment and the 8th Amendment to the U.S. Constitution. Extended solitary confinement for over 15 days should therefore be banned.
Solitary confinement isolates prisoners in a small concrete cell for about 23 hours a day. Food slides through a slot in the door and is eaten alone. Exercise consists of pacing in the small cell. The extreme mental and physical isolation of solitary confinement leads to a significant deterioration of mental health among prisoners, especially those with pre-existing mental conditions. A literature review of four decades of published studies on extended solitary confinement by Professor Craig Haney shows negative mental effects, such as panic, rage, paranoia, self-mutilations, and insomnia. A study by the NYC Department of Health and Mental Hygiene shows that solitary confinement increases the propensity to self-harm. Fifty-three percent of the 2182 acts of self-harm in the New York City jail system from 2010 to 2013 were done by prisoners in solitary confinement, even though they only represented 7.3% of the general prison population. Furthermore, a study of Danish prisons shows that prisoners subject to solitary confinement for longer than four weeks were 20 times more likely to be put in the hospital for psychiatric reasons.
These negative mental health effects are particularly damaging to those with pre-existing mental illnesses. Prisoners with pre-existing mental health problems are four times more likely to be held in solitary confinement, according to a Washington State study. The ACLU’s National Prison Project shows that, given the especially severe effects of solitary confinement on the mentally ill, every claim in federal court made by mentally ill prisoners who have been held in solitary confinement has been found valid.
In addition to having negative mental health effects, solitary confinement does not achieve its intended goals of reducing violence among prisoners or decreasing recidivism. The opening of supermax prisons that rely heavily on solitary confinement, like Tamms in Illinois, did not decrease inmate-on-inmate violence and achieved mixed results with prisoners-on-staff violence. Furthermore, the reduction in size of supermax prisons in Colorado, Maine, and Mississippi did not result in an increase in prison violence. In fact, solitary confinement may give rise to violent tendencies because it causes prisoners to feel mistreated and has negative mental health effects. In the United States, where two-thirds of 700,000 prisoners released every year are rearrested in three years, solitary confinement only perpetuates recidivism. A study of Florida prisons showed that prisoners who had undergone solitary confinement had a 24.2% chance of being reconvicted of a violent crime, compared to 20.5% of general prisoners.
International human rights authorities oppose extended solitary confinement. In 2011, the U.N. Special Rapporteur on Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment reached the conclusion that solitary confinement must be limited to 15 days or less because it violates the Convention on Torture and Other Cruel, Inhuman, and Degrading Treatment or Punishment (CAT). Article 1 of CAT defines torture as “any act by which severe pain or suffering, whether physical or mental, is intentionally inflicted on a person for such purposes as . . . punishing him for an act he or a third person has committed or is suspected of having committed.” Solitary confinement intentionally deprives meaningful social contact, thereby inflicting severe mental pain on prisoners and exacerbating mental illness. Accordingly, solitary confinement constitutes torture.
Despite recent advances in state courts, such as New York, and the push by international human rights advocates, U.S. federal courts have not taken the necessary final step. Solitary confinement should be considered "cruel and usual punishment" under the 8th Amendment to the Constitution because psychological damage caused by solitary confinement can prevent a prisoner from properly functioning in society and can endanger his physical state through self-harm. This should be considered in light of the fact that solitary confinement does not achieve its intended benefits of reducing levels of prisoner violence and recidivism. Federal courts should thus rule that extended solitary confinement violates the 8th Amendment and the practice of solitary confinement over 15 days should no longer be allowed in prisons.
 Craig Haney, Mental Health Issues in Long-Term Solitary and "Supermax" Confinement (Crime and Deliquency, 2003).
 Homer Venters et al, Solitary Confinement and Risk of Self-Harm among Jail Inmates (American Journal of Health, 2014).
 DM Sestoft et al, Impact of Solitary Confinement on Hospitalization Among Danish Prisoners in Custody (International Journal of Law and Psychiatry, 1998).
 E. Shira Gordon, Solitary Confinement, Public Safety, and Recidivism (University of Michigan Law Reform, 2014).