A new story from The New York Times highlights a disturbing trend at Rikers Island: Violence has surged in the New York City jail, with use of force by guards jumping 240 percent in the past decade. That’s as the daily inmate population has declined by almost 15 percent over the same period.

Since Dec. 31, there have been at least 12 reports of inmates being slashed or stabbed. Interviews with current and former inmates also paint gruesome scenes of beatings by guards.

The Times article follows a series of Associated Press reports of violence on Rikers Island, including a recent revelation that nearly a third of the 1,257 inmate injuries between April 2012 and April 2013 that were allegedly sustained from use of force by correction officers involved a blow to the head – a tactic that is supposed to be a guard’s last resort.

And an AP story today also revealed that a 56-year-old, mentally ill inmate – a former Marine – was found dead last month in a cell that officials say had overheated to at least 100 degrees.

So what’s behind the spike in mayhem? In a report last year, Dr. James Gilligan, a clinical professor of psychiatry at New York University, said the heavy use of solitary confinement and force at Rikers Island has contributed to a “subculture of violence” among inmates, particularly those with mental illnesses.

According to the New York City Department of Correction, 40 percent of inmates at the jail have a diagnosed mental illness. And that includes the hundreds of teenagers incarcerated at Rikers – almost half of whom have mental health issues.

The rate is even higher for those in solitary. As CIR’s Trey Bundy and Daffodil Altan recently reported, about 100 teenagers are held in isolation at Rikers Island on any given day. And nearly three-quarters of them have a diagnosed mental illness.

The rise in mentally ill inmates at Rikers and correctional facilities across the U.S. has left corrections staff ill-equipped to deal with those needs, experts say. As Norman Seabrook, president of New York City’s correction officers union, told CIR, “We don’t have the experience to deal with a person with psychological problems. We’re not doing enough because they shouldn’t be brought to us.”

According to the city’s Department of Health and Mental Hygiene, Rikers inmates in solitary confinement are seven times more likely to hurt or mutilate themselves than those in the general population. And there’s strong evidence that extended periods of solitary confinement can lead to mental illness and suicide.

Former correction officials say solitary confinement contributes to an increase in violence. Dr. Robert Cohen, former director of medical services at Rikers who now is on the New York City Board of Correction overseeing the jail, recently told CIR, “We know that, particularly for mentally ill people, the longer they are in solitary confinement – the fact of being in solitary confinement – increases the chance of serious violence. Serious, in particular, violence in the interaction with correction staff both during and after their release from solitary confinement while they’re still on Rikers Island.”

Cohen added: “It does not make you a better person to be locked up in a cage for what really amounts to 24 hours a day.”

A recent study by the American Journal of Public Health also found that New York City jail inmates sent to solitary confinement are nearly seven times more likely to inflict self-harm than those never assigned to it.

Meanwhile, correction officers defend solitary confinement and other disciplinary policies as a means to get through the day.

“We have had inmates bite off the fingers of correction officers so that they now have eight-and-a-half and nine fingers as opposed to 10,” Seabrook told CIR. “Until you’ve walked in the shoes of a correction officer inside the city’s jail system, please don’t pass judgment on us, because you know what? It’s a tough job.”

CIR will continue to report on solitary confinement issues in the coming weeks, so stay tuned. In the meantime, you can read our investigations so far, watch our segment with PBS NewsHour and get an account of one teen’s experience in solitary confinement on Rikers Island in our new animation below:

Cole Goins is the director of community engagement for Reveal, where he cultivates partnerships that blend in-depth journalism and creative public engagement. He has built and supported distribution networks, spearheaded arts-based initiatives such as the Off/Page Project, led social media and audience strategy, and facilitated statewide media collaborations. He was a senior fellow in the 2015 USC Annenberg Health Journalism Fellowships, mentoring five journalists on approaches to community engagement. Previously, Goins was the engagement editor at the Center for Public Integrity, where he led audience development initiatives and multimedia features for award-winning investigative projects. He earned a degree in journalism from the University of North Carolina at Chapel Hill, where he worked as music director for WXYC, the student-run radio station. He is based in Reveal's Emeryville, California, office.