Skip to content

Can solitary confinement be justified?

This month an article published in the American Journal of Public Health (AJPH) outlined the results of a study on self-harm amongst jail inmates in New York City. Data on all jail admissions between January 2010 and October 2012 was analysed and the authors noted the following: “We found that acts of self-harm were strongly associated with assignment of inmates to solitary confinement. Inmates punished by solitary confinement were approximately 6.9 times as likely to commit acts of self-harm after we controlled for length of jail stay, SMI [serious mental illness], age, and race/ethnicity.”

This research provides an interesting springboard for a discussion. Can solitary confinement ever be justified, and if so, in what circumstances?

In Queensland, Australia, in response to a perceived problem of criminal motorcycle gang activity, the incumbent government has introduced a new ‘top-up’ regime of mandatory imprisonment for those who are deemed ‘participants’ in a criminal association. Additionally, there is a new imprisonment policy for criminal associates, which will be the focus here.

The new policy provides that members of ‘criminal motorcycle gangs’ (CMGs) are to be held for the duration of their sentence in accordance with a ‘Restricted Management Regime’ that includes the following conditions:

  1. Out of cell time restricted to at least two daylight hours a day [an affidavit clarifies that this means 22 hours of solitary confinement a day, with the only exception being if there are scheduled appointments to attend, such as medical appointments].
  2. CMG prisoners will only be entitled to a 1 hour non-contact personal visit with family members per week.
  3. The wearing of the CMG prisoner uniform [a pink jumpsuit – different from the clothing of regular prisoners].
  4. No TVs in cells.
  5. No access to gymnasium facilities/oval.
  6. CMG prisoner phone calls restricted to seven personal calls per week (6 minute duration).

Under this policy, members of criminal motorcycle gangs will serve the entirety of their prison sentence in solitary confinement. Under the new mandatory regime, this involves a minimum of 15 years for associates, or 25 years for office-holders. Can such a regime be justified by reference to the key aims of the criminal justice system?

The starting supposition for what follows was best articulated by the 18th century legal reformer and philosopher Jeremy Bentham, in An Introduction to the Principles of Morals and Legislation:

The general object which all laws have, or ought to have, in common, is to augment the total happiness of the community; and therefore, in the first place, to exclude, as far as may be, every thing that tends to subtract from that happiness: in other words, to exclude mischief.

But all punishment is mischief: all punishment in itself is evil. Upon the principle of utility, if it ought at all to be admitted, it ought only to be admitted in so far as it promises to exclude some greater evil.

When it comes to spending limited public resources on criminal justice, we should hope to achieve something. Punishment is only justified when its benefits outweigh its costs. So, what are the benefits of solitary confinement?



Imprisonment can be justified when it protects the public from serious threats. This is a possible justification for locking up those who are likely to re-offend, and perhaps even a reason to detain some people indefinitely.

However, solitary confinement achieves no greater degree of incapacitation than regular imprisonment, insofar as members of the public are concerned. Once in prison, the justification for using solitary confinement is dependent on a serious risk being presented to fellow prisoners or prison staff. Seriously dangerous prisoners may be justifiably detained solitarily, insofar as this is necessary to remove the danger they pose.

Incapacitation does not support a blanket policy of solitary confinement.



Another justifiable aim of the criminal justice system is reformation of character or rehabilitation. According to Dr Sharon Shalev in A Sourcebook on Solitary Confinement, this was one of the historic rationales for solitary confinement. As she writes:

Solitary confinement was first widely and systematically used on both sides of the Atlantic in the ‘separate’ and ‘silent’ penitentiaries of the 19th century, with the aim of reforming convicts. It was believed that once left alone with their conscience and the Bible, prisoners would engage in inner reflection, see the error of their ways and be reformed into law abiding citizens.

She continues:

It soon transpired, however, that rather than being reformed, many prisoners became mentally ill, and there was little evidence that the newly built, expensive prisons were more successful than their predecessors in reducing offending.

Research shows that solitary confinement can both inflict and exacerbate a whole spectrum of serious psychiatric conditions, from severe depression to visual and auditory hallucinations. One study from Denmark found that, after four weeks of being detained in solitary confinement, the probability of being admitted to hospital for psychiatric reasons was about twenty times as high as compared with an individual remanded in non-solitary confinement. Another study found that, over time, symptoms experienced by isolated prisoners were “likely to mature into either homicidal or suicidal behaviour.” Dr Shalev also notes that the ‘totality of control’ experienced by these prisoners results in some becoming so reliant on the prison to structure their lives that, “they lose the capacity to exercise personal autonomy.”

At best, mental illnesses are a serious burden for a particular individual, and a drain on public health resources. At worse, they put other members of the community at risk. Besides the risk of inflicting a serious mental illness, a person held in solitary confinement for a significant period of time is likely to lose – if they ever had them – the social skills or intellectual abilities / knowledge necessary to engage in a meaningful occupation. No attempt is made at providing these.

The hope that hardened criminals can be made into exemplary citizens may be forlorn. But the risk they present once released should at least be mitigated, and, if possible, they should be provided with the skills necessary to successfully reintegrate.

Solitary confinement cannot be said to reform or rehabilitate prisoners.


Community satisfaction

Victims and members of the public have an interest in seeing wrongdoers punished. This could provide a justification for increasing a punishment in some circumstances, other things being equal. However, the extent to which victim and public satisfaction should be balanced with other considerations is a vexed question.

A second aspect to this issue is the empirical matter of what the public actually consider a just punishment. One rationale for the changes in Queensland, according to the government, is that judges deliver weak penalties. They are said to be out of touch with community expectations and live in ‘ivory towers’. However, the only thorough investigation of the issue, a 2011 report by the Australian Institute of Criminology, paints a more positive picture of judicial sentencing. According to data from the Tasmanian Jury Sentencing Study, jurors who were informed of the facts of a case, and had read the decision justifying the sentence, reported high levels of satisfaction with judicial sentencing: 90% considered the sentence ‘appropriate’. When asked to indicate what an appropriate sentence would have been, 52% of jurors selected a more lenient sentence than the judge.

The interest of members of the public and victims in seeing an offender punished may provide some rationale for solitary confinement, at least when existing penalties are clearly regarded as too weak. Whether this interest would be sufficient on its own to justify solitary confinement is doubtful, given the serious harms. It may be justifiable if coupled with other benefits.



Of all the rationales discussed, deterrence has the greatest chance of being able to justify a general policy of solitary confinement. However, here we get into difficult empirical territory. Unfortunately there does not seem to be any research on solitary confinement as a deterrent specifically, so here we focus on related research.

Many people have a gut feeling that tougher penalties must work to reduce crime. In general this means a call for longer sentences. The empirical literature on whether longer sentences reduce crime is somewhat equivocal, but the general view seems to be that longer sentences only really reduce crime insofar as they incapacitate; the general deterrent effect of lengthier sentences is weak to non-existent. The New South Wales (Australia’s most populous state) Bureau of Crime Statistics and Research, in a 2012 study, conclude that for property and violent crime, “Increasing the length of stay in prison beyond current levels does not appear to impact on the crime rate after account for increases in arrest and imprisonment likelihood.”

Even if solitary confinement were to deter crime, it would be relevant how it fares in comparison with alternatives. And here the empirical literature is clearer. According to a number of studies, much larger deterrent effects can be achieved by increasing the likelihood of being punished, as compared with increasing the severity of the punishment. Indeed, that was the conclusion of the 2012 study cited just above. The authors concluded that, “Policy makers should focus more attention on strategies that increase the risk of arrest and less on strategies that increase the severity of punishment.” In the words of Lana Freisen, from the University of Queensland’s School of Economics, “increases in the probability of punishment have a larger and more significant impact than increases in the severity of punishment.”

Using limited resources on better policing and enforcement of the laws may achieve larger deterrent effects without the serious harms that solitary confinement brings.


Concluding thoughts

Solitary confinement is an extreme prison practice. Its propensity to inflict serious mental illnesses means that its use must be restricted to circumstances in which its benefits clearly outweigh its costs. It may be appropriate in some prison disciplinary situations, in order to remove a risk to prison staff or other prisoners. However, as a general detention policy, it can probably only be justified by evidence that it would have powerful deterrent effects that cannot be achieved through less costly means, possibly coupled with evidence of a community expectation of tougher punishment.

Solitary punishment can have a legitimate penal purpose. However, one doesn’t have to be a bleeding-heart to believe that it is likely to be a bad idea except in very exceptional circumstances. Politicians who seek to deploy it should justify its use by reference to evidence of tangible benefits and not hollow rhetoric.


Share on