Jonathan McClard, 16, “leaned forward” toward an officer. A 17-year-old in California “made a smart remark.” Kalief Browder, 16, told another inmate to stop throwing shoes at people. Albert Woodfox, who was in solitary confinement longer than any other American, was too political for guard administrators’ tastes. Barbra Perez, a trans woman, was placed in solitary “for her own protection.” Many are accused of having gang affiliations by inmates being questioned under duress. Some are just on a prison guard’s bad side.

In other words, prison guards and administrators often throw individuals in solitary for minor, arbitrary reasons. Zoom out: Overcrowded prisons and inadequate staffing mean that inmates are placed in solitary when there is no physical room in general holding, or no staff to attend to them. Zoom out one more time: The system of mass incarceration and the sheer number of people being sent to jail and kept waiting for trials produce chaotic backlogs, and prisoners’ voices get lost.

The paths that lead to time in solitary confinement—also known as “the hole,” “SHU” (Segregated Housing Unit), “the box”—vary from institution to institution, but they are also the result of a criminal justice system that emphasizes control over rehabilitation. The cruel irony is that juvenile inmates under 21, who experts agree have the least culpability and highest potential for rehabilitation, are far more likely to “act out” and be placed in isolation as punishment.

Click here to watch the trailer for time: the Kalief Browder Story | Premieres March 1

But inmates also land in solitary for their “protection,” perhaps because of their size, or age, or sexuality. “There’s a whole range of reasons that kids can end up in solitary that have nothing to do with their behavior,” says Marc Schindler, the executive director of the Justice Policy Institute, one of the leading organizations in the Stop Solitary for Kids coalition.

Data that measures the movement of inmates through our criminal justice system is spotty at best, and even less comprehensive when it comes to juvenile inmates. In 2013, the Annie E. Casey Foundation estimated that roughly 70,000 inmates 21 or younger were imprisoned in the United States, while a 2010 report by the Office of Juvenile Justice and Delinquency Prevention found that some 35 percent of surveyed juvenile inmates had been isolated during their sentence. Solitary confinement is considered a form of torture by more than one human rights organization, and it falls disproportionately, like the prison system as a whole, on black and brown prisoners. It also has not been shown to reduce violence in prisons or to improve inmate behavior. “If you talk to people in solitary confinement, very few of them are out of control,” says Dr. Terry Kupers, a psychiatrist who has studied the effects of solitary confinement for decades. “Most of them are quiet and thoughtful.

“They don’t know why they have to spend so much time in solitary.”

The psychological effects perpetrated by solitary confinement are difficult to quantify and summarize, partly because those effects run the gamut of disordered behavior. A host of studies and experts have pointed to anxiety and panic attacks, hallucinations, loss of impulse control, depression, memory loss, and the overall decline of cognitive function. In young inmates, those effects are amplified as their developing brains struggle to adapt to conditions that run counter to healthy, socialized behavior.

Most alarming, rates of self-harm and suicide skyrocket in inmates who are held in solitary confinement. Somewhere between three and eight percent of the country’s prison population, they account for 50 percent of prison suicides. “That’s a stunning statistic that says isolation fosters or causes suicide,” says Kupers. Self-harm, he says, “is something I don’t otherwise see in grown men. Cutting becomes much more common with juveniles. In solitary confinement, it becomes an epidemic.”

When the ACLU filed a lengthy report in 2012 on juvenile inmates in solitary confinement, they included accounts from young people that need neither explanation nor embellishment:

“I felt doomed, like I was being banished...like you have the plague or that you are the worst thing on earth.”

“I felt an inner pain not of this world.”

“I feel like I am alone, like no one cares about me—sometimes I feel like, why am I even living?”

“I just felt like I wanted to die, like there was no way out…. I couldn’t breathe.”

According to Kupers, there is also visible, biological proof that solitary derails a teenager’s brain development, not only increasing the likelihood of disordered behavior, but also making them less receptive to rehabilitation. In adolescent brains, the pre-frontal cortex (which controls higher-level thinking, such as judgment and morality) and the temporal lobe (which is responsible for processing and interpreting sensory information) are still adjusting their interaction with each other, which is why teenagers are more likely to be impulsive, irritable, or impatient.

“The effect of isolation is to exaggerate the activity in the temporal lobe, which drives that free-floating anxiety,” Kupers says. “There’s also an inability to develop the pre-frontal cortex because no meaningful activity is going on…. That’s a very dangerous combination which probably means they’re going to get in more trouble as they get older.”

Anything that would provide the needed meaningful activity—education, counseling, sufficient exercise—is denied to juveniles in solitary. The burden of solitary is not only psychological decline but also the lost opportunity for education and rehabilitation. “In solitary,” says Schindler, “you’re cut off from those kinds of programs.”

Schindler and Kupers point to a nonliteral type of death as well—a social, emotional death, in which inmates cease to be social, relational beings. “The average story,” says Kupers, “is ‘I worked so hard to control my anger so I wouldn’t get into more trouble, but then I start suppressing all my feelings. I lose touch with what I’m feeling. Then I don’t really know what I feel.’”

Inmates in solitary can try to fight that psychic decay by yelling to each other through the walls or talking briefly with prison guards, Kuper says, but over time, they stop trying. They are more likely to lie listlessly in their cells, rejecting whatever brief chances to communicate they get. “I asked them, ‘Why don’t you talk?’ And they say, ‘Well, I don’t have anything to say.’”

The worst part about solitary confinement is that it doesn’t end, even when it does. As Brian Nelson, a former inmate who spent time in solitary, wrote in Hell Is a Very Small Place: “The worst part is I think I’m still there. I’m so afraid I’m gonna wake up and be back there.” Enceno Macy, who was first put in solitary when he was only 13, wrote that solitary “encouraged me to retreat deep into a demented reality where I was so alone, it made me feel as though I wasn’t meant for this world. I still feel that way to this day—like I don’t fit.”

Kalief Browder, after spending three years in Rikers Island, two of which were in solitary, took to locking himself in his room and pacing. He had always maintained his innocence, and finally the case was dismissed because there was no evidence of his guilt. After he returned home, his family members said he was paranoid and withdrawn, though growing up, he had been known as fun, smart, social, engaged. His mother, Venida, used to call him “Peanut.” After his time in prison, he told her more than once that he didn’t know if he could trust her. “Mentally, he was still in Rikers,” she told The Marshall Project.

“His personality was gone. His happiness was gone. You saw a darkness in him, versus the bubbly, the energetic, the outgoing from before,” says Deion Browder, Kalief’s older brother. “He became a shell.”

“We really have to help them dig themselves out of a hole that they were placed in, quite literally,” says Schindler. “We have to recognize the induced trauma.” Some states are trying. Missouri, for example, eliminated solitary holding cells for juveniles in favor of dorm-like settings. In Indiana and Ohio, solitary for juveniles is severely restricted. “There’s no question that it can be done,” Schindler says, but states and institutions must be willing to invest the time and money required for programs that improve staff-inmate relationships and reduce solitary confinement for juveniles or, better yet, eliminate it.

But the criminal-justice and prison system that leads to a “culture of excessive solitary confinement” must also change, he says: “The first thing we should do is not put [juveniles] in solitary confinement at all.”