The Neuroscientific Effects of Solitary Confinement on the Brain and Mental Health of Prisoners
On this European Mental Health Week, we join the growing global call to end the use of solitary confinement. In this article, we highlight its devastating impact on mental health and human dignity, and we stand alongside other organizations demanding the elimination of this harmful practice. To mark this occasion, we offer a legal and neuroscientific overview of the standards, risks, and human rights concerns associated with solitary confinement.
According to the European Prison Rules, solitary confinement involves placing prisoners alone in a cell, by removing them from meaningful association and contact with other prisoners. In terms of the European Committee for the Prevention of Torture (CPT), this kind of isolation should only be used in exceptional circumstances and for the shortest possible time, due to its serious impact on a prisoner’s mental, physical, and social well-being. The UN’s Nelson Mandela Rules go further, defining prolonged solitary confinement as more than 15 days and stating that it should never be used on vulnerable individuals. These standards make it clear that solitary confinement should only be used as a measure of last resort. Yet, despite these safeguards, it remains widely used in many prison systems – raising ongoing concerns about its effectiveness, legality, and the harm it causes to human rights and prisoner well-being.
Historically, solitary confinement was introduced with the idea that it could help rehabilitate prisoners by encouraging them to reflect, experience remorse, and change their behaviour through the “power of silence”. But reports from the United Nations (UN) and rulings by the European Court of Human Rights (ECtHR) show that instead of assisting prisoners to change, solitary confinement causes significant harm to the brain and increases the chances that prisoners will end up back in prison. With all the clear evidence of the damage it does, experts in neuroscience and human rights are calling for an end to this practice – and for it to be replaced with safer, more humane alternatives.
Scientific research has established that prolonged solitary confinement causes severe neurological harm. Legal scholar and Assistant Professor of Criminal Law at IE University Law School, Dr. Federica Coppola’s article on the effects of the brain “in solitude”, demonstrates how isolation leads to measurable changes in brain structure and function. Studies using brain imaging have shown that prisoners subjected to long-term solitary confinement exhibit shrinkage in the hippocampus, the region responsible for memory and spatial orientation, as well as increased activity in the amygdala, which is linked to fear and anxiety.
Therefore, many prisoners in solitary confinement experience hallucinations, paranoia, and severe cognitive impairments, indicating a deterioration of brain function that can persist long after their release. This is because prolonged isolation reduces levels of essential neurotransmitters like serotonin and dopamine, contributing to heightened depression, suicidal ideation, and psychotic symptoms.
In addition to its neurological harm, the United Nations report by the Special Rapporteur on torture describes how prolonged solitary confinement poses a threat to fundamental human rights. Solitary confinement can amount to cruel, inhuman, or degrading treatment – and in severe cases, even torture. The report shows that solitary confinement undermines rehabilitative goals and infringes on the dignity and well-being of those subjected to it. In addition, solitary confinement used as a punishment, during pretrial detention to extract confessions, or without a definite term, increases the risk of human rights abuses going undocumented and unchallenged. Under these circumstances, and when conditions involve total lack of human contact or poor physical environments, the UN calls for strict limitations. In many cases, the UN and other human rights organizations call for an outright ban of this practice, in order to align prison conditions with international human rights standards.
The European Court of Human Rights recognized these harmful effects in the case of Schmidt and Šmigol v. Estonia (2023). In this ruling, the Court found that the prolonged use of solitary confinement violated Article 3 of the European Convention on Human Rights, which prohibits inhuman or degrading treatment. The decision reinforced the growing consensus that solitary confinement is not only ineffective but violates fundamental rights and is deeply damaging to the mental and neurological well-being of prisoners.
ANTIGONE, an NGO advocating for human rights in the criminal justice system, published a joint statement together with an international working group of experts. The statement outlines several alternatives to solitary confinement like restorative justice and conflict resolution. These methods encourage individuals to understand the impact of their actions and take responsibility in a constructive way. To reduce violence and self-harm, facilities should make sure prisoners have time outside their cells, have access to social skills programs, and have personalized support such as creative activities tailored to their interests.
Mental health professionals should take an active role by stepping in during crises to carry out timely assessments and advocate for alternatives to solitary confinement, rather than contributing to its use. For minor infractions, it is better to use short period isolation (no more than 12 hours) in single cells within regular prison units, without cutting off meaningful human contact. Just as importantly, these approaches should go hand in hand with regular training for prison staff in trauma-informed care, de-escalation strategies, and cultural awareness. This helps ensure that responses are not only ethical, but also effective and humane.
As we mark European Mental Health Week, it is essential to recognise that prolonged solitary confinement is not just a threat to mental health—it is a violation of human rights. The neuroscientific evidence is clear: isolation harms the brain, deepens psychological suffering, and works against the very goals of rehabilitation and reintegration. Rather than promoting reflection or reform, solitary confinement often leads to mental, social and emotional deterioration.
At Fair Trials, we believe that the criminal justice system must uphold human dignity, especially for those most at risk. A system that relies on outdated, degrading practices is no longer acceptable. It is time to move beyond punishment for its own sake and towards an approach that protects, restores, and truly rehabilitates. Legislative reform and prison policies must reflect this shift—grounded in research, responsive to mental health needs, and committed to humane alternatives.
This article was written by Angelica Vieira, a member of Fair Trials’ European Impacted Persons Advisory Council (EIPAC) and a lawyer. Edited by Ángela Rodríguez, Fair Trials Communication Manager.
