physical or mental, is intentionally inflicted on a person for such purposes as obtaining from him or a third person information or a confession, punishing him for an act he or a third person has committed or is suspected of having committed, or intimidating or coercing him or a third person, or for any reason based on discrimination of any kind, when such pain or suffering is inflicted by or at the instigation of or with the consent or acquiescence of a public official or other person acting in an official capacity.”
According to this definition, solitary confinement is a method of torture since it inflicts a severe level of mental pain and suffering, shown to cause psychological effects such as paranoia, anxiety, panic attacks, depression, insomnia, or hallucinations. Although it's unknown what percent of the inmates were mentally ill before being committed to a supermax facility, the percent of prisoners that struggle with mental illness was found to reside in the range of 22 to 45 percent.