By REMA RAHMAN, Associated Press

Troy Anderson is a mentally ill inmate in isolation at the Colorado State Penitentiary, deemed for more than a decade too dangerous to be among other offenders.

His lawyers argue, however, that prolonged solitary confinement is contributing to a vicious cycle, making his psychiatric conditions worse and resulting in misbehavior that warrants further punishment.

Prison officials defend the practice, saying administrative segregation, which can include up to 23 hours a day alone in a concrete cell, is a fundamental part of security.

Art Leonardo, executive director of the North American Association of Wardens and Superintendents, says keeping prisoners away from the general population is a way to “keep them from being harmed.”

But prisoners’ rights advocates around the nation say putting mentally ill inmates in long-term solitary confinement amounts to cruel and unusual punishment. In some states, activists are pushing court challenges to…