You might assume all inmates sent to solitary are the “worst of the worst”—rapists and murderers who continue their violent ways even behind bars. But in fact, many are placed in solitary for nonviolent offenses, and some are not even criminals, having been arrested on immigration charges. Others are thrown into isolation cells “for their own protection” because they are homosexual or transgendered or have been raped by other inmates.

Whatever the reasons, such extreme isolation and sensory deprivation can take a severe, sometimes permanent, toll on emotional and mental health. Researchers have found that prisoners in solitary quickly become withdrawn, hypersensitive to sights and sounds, paranoid, and more prone to violence and hallucinations. Craig Haney, a professor of psychology at the University of California, Santa Cruz, has documented several cases of individuals with no prior history of mental illness who nonetheless developed paranoid psychosis requiring medical treatment after prolonged solitary confinement. As damaging as the consequences are for otherwise healthy adults, they are even worse for adolescents, whose brains are still in their final stages of development, and the mentally ill, who already struggle to maintain a solid grasp on reality. About half of all prison suicides occur in isolation cells.