Updated: May 6, 2019 2:25PM

A lawsuit filed on Monday by the American Civil Liberties Union claims that the long-term use of solitary confinement at two of Virginia’s toughest prisons has caused “severe physical and mental health damage” to many of the housed inmates, some of which have experienced hallucinations, post-traumatic stress disorder, and suicidal thoughts.

The complaint was filed in the U.S. District Court in Richmond, Virginia, by the American Civil Liberties Union on behalf of a dozen prisoners who were placed in solitary confinement between two to 24 years. The practice is known to be widespread and often used as punishment for minor infractions of prison rules.

After a prisoner enters solitary confinement, they are put into a “step-down program” that Virginia claims enables them to rejoin the general population of the prison depending if their behavior improves significantly.

However, the lawsuit claims that the program is a sham designed to keep inmates locked away to make use of available space in the prisons system.

“It’s this sort of Kafkaesque, never-ending cycle of being trapped in solitary confinement, not achieving perfection,” Amy Fettig, deputy director of the ACLU’s National Prison Project, said by phone.

The Virginia Department of Corrections did not have any comment regarding the lawsuit.