Part 3 113 characteristics of each detainee that make him or her more or less vulnerable to those effects.131 Solitary confinement should remain exceptional. Case Study – Solitary confinement* X is suspected of being involved in terrorist activities and is placed in solitary confinement for security reasons. Despite domestic regulations limiting the use of solitary confinement to up to 30 days, X is systematically put back in isolation after very short breaks. His solitary confinement lasts close to 18 months in total. Different reports by NGOs allege that the prolongation of his confinement aims at countering his resistance, pressuring him and causing him stress. Evidence indicates that X is also subjected to practices that include withholding of clothes or of hygienic products, permanent light in his cell, cultural and religious harassment, intimidation, total sensory deprivation and total social isolation. X is also denied access to independent tribunals. Question: Does X’s solitary confinement constitute torture or cruel, inhuman or degrading treatment or punishment? Placing a dangerous terrorism suspect in solitary confinement is an extraordinary measure that may be necessary for security reasons. However, depending on its length, purpose, conditions and other practices inflicted on the detainee, solitary confinement may amount to torture or cruel, inhuman or degrading treatment. • Length of the solitary confinement: the longer the isolation, the greater the risk of serious and irreparable harm to the detainee. A “prolonged solitary confinement”, defined by international bodies as exceeding 15 days, might amount to torture or other cruel, inhuman or degrading treatment. In the present case, the initial period of solitary confinement exceeded twice this threshold, and lasted 18 months in total. The uncertainty surrounding the length of solitary confinement exacerbated X’s pain and suffering. 131 United Nations Special Rapporteur on torture and other cruel, inhuman or degrading treatment or punishment, Juan Méndez, Report to the General Assembly, 5 August 2011, A/66/268, paras. 70–78, <http://www.un.org/Docs/journal/asp/ws.asp?m=A/66/268>.