For the average Yalie, 23 hours flies by. It’s hard to fit in sleep around four classes, three meals, lab, talking and laughing with 10 different friends, 8,000 steps, 150 pages of reading, two review sessions, 10 Facebook checks, a jog up Science Hill, a shower, 20 text messages to friends, a phone call with a parent, a play, lecture, performance, Master’s Tea and the obligatory Netflix binge.

For a juvenile in solitary confinement, 23 hours is an eternity. Alone in an 7-by-12 cell without books or contact with the outside world, one Florida youth in isolation told the American Civil Liberties Union in 2011, “The only thing left to do is go crazy -— just sit and talk to the walls.”

Even as far back as 1890, we’ve known the troubling consequences of solitary confinement. In an 1890 Supreme Court case which prohibited death row inmates from being held in solitary confinement, the Court said, “a considerable number of the prisoners fell, after even a short confinement, into a semifatuous condition, from which it was next to impossible to arouse them, and others became violently insane; others still, committed suicide, while those who stood the ordeal better were not generally reformed.”

Today, solitary confinement is common for adults, and the practice has been extended to juveniles. It is difficult to determine the exact number of juveniles who are currently held in solitary confinement, but across the country, there are jails that isolate their entire juvenile populations in solitary confinement for the duration of their pre-trial sentence. When juveniles are transferred to adult prisons, they are often isolated “for their own protection.” In an incredibly bone-headed move, institutions sometimes use solitary confinement as a treatment method for juveniles who are recuperating after a suicide attempt. But it is also used punitively: Minor infractions, such as insubordination, can land a juvenile in isolation for up to 90 days.

Whatever the reason, juveniles’ experiences in solitary confinement are strikingly similar — and horrific. Kids in solitary confinement may be barred from regular programming including education, mental health services, recreation and social interaction with their peers.  Many are cut off from their family and denied visits, phone calls, letters and other such privileges. Such deprivation is devastating for their development and mental health. Its effects are long-lasting: George Chochos DIV’16, a second-year Yale Divinity School student who spent 11 years in prisons in New York, still experiences the adverse effects of the 20 days he spent in solitary confinement. Even today, he finds it difficult to be in extremely crowded places or to be left alone with his thoughts for an extended period of time.

For a 2011 report, Growing Up Locked Down, Human Rights Watch and the ACLU spoke to youth who reported experiencing thoughts of suicide and self-harm, auditory and visual hallucinations, nightmares, loss of sleep and uncontrollable anger. Many adolescents carry a history of abuse, trauma, neglect and mental health problems. Kids may emerge from solitary confinement 30 pounds lighter, jittery and scarred physically and mentally. To even the most peaceful mind, 23 hours of isolation, sometimes for six months on end, is traumatic. When juveniles as young as 13 are subjected to solitary confinement, it’s torture.

Putting juveniles in solitary confinement violates domestic and international principles: Solitary confinement, though unfortunately far from “unusual,” is nevertheless cruel and violates both the Constitution and a whole host of international agreements.

There are glimmers of progress: States such as Mississippi and Colorado are rethinking solitary confinement and seeing the number of violent incidents and associated costs go down. New York City announced a ban on solitary confinement for 16- and 17-year-olds at Rikers Island. These statewide efforts are commendable, but it is high time for national change.

More than 900 Yale students signed letters in support of “second look” legislation — sentencing policy reform that takes into account juveniles’ incomplete neurological development and complicated backgrounds.

I urge you to stand, once more, with youth who have been caught up in the criminal justice system. This time, fight for youth whose only companions are a metal toilet, desk and bed, who yearn to see a sliver of sunlight or talk to another inmate, whose mental health deteriorates with every hour they must stare at excrement-covered walls and attempt to stay sane. Stand with the Yale Undergraduate Prison Project and the Student Prison Alliance, and sign the ACLU’s petition, lobbying the Attorney General to ban the use of solitary confinement on anyone under the age of 21.

Yale students are some of the busiest juveniles I know. If anyone knows the value of 23 hours, it’s us.

Charlotte Finegold is a sophomore in Berkeley College and co-director of advocacy and awareness for the Yale Undergraduate Prison Project. Contact her at charlotte.finegold@yale.edu .