Terry Kupers

But that can only do so much.

The United Nations, many human rights organizations, and experts classify this kind of forced, prolonged isolation as torture.

And yet, it's something imprisoned people in many countries endure.

Also called solitary confinement or restrictive housing, the practice is most common in the United States.

In 2019, more than 120,000 U.S.

prisoners lived in solitary confinement, spending 22 to 24 hours a day in mostly windowless cells spanning roughly 6 by 9 feet.

Quaker groups introduced solitary confinement to U.S.

prisons in the late 1700s as an alternative to corporal punishment, believing it could bring about reflection and penitence, hence penitentiary.

But the practice quickly faced criticism from public figures all the way to the Supreme Court.

Charles Dickens, for one, condemned solitary confinement as worse than any torture of the body.

Its use dwindled, but then, in the 1980s, alongside more punitive, tough-on-crime laws, U.S.

prison populations skyrocketed.

As prisons grew crowded, incidences of protests, rebellions, and violence grew, and prison authorities increasingly used solitary confinement to maintain control.

Many people have been placed in solitary confinement for minor, nonviolent infractions, like talking back to prison guards.

And solitary confinement is harmful to everyone, but many who've experienced it have pre-existing mental health disorders, which it only exacerbates.

Solitary confinement also seems to have lasting effects that make readjusting to life outside of a cell difficult.

People who have gone through solitary confinement are three times more likely to show signs of post-traumatic stress disorder.

And they commonly report experiencing shifts in their personalities, increased anxiety and paranoia in otherwise ordinary situations, and difficulty concentrating and connecting with others.

Some states have restricted the use of solitary confinement in cases involving serious mental illness, children, or pregnancy.

and some have adopted 15- or 20-day limits for everyone.