US Attorney General Eric Holder on Wednesday called for an end to the “excessive” use of solitary confinement in juvenile facilities, especially condemning the practice of isolating youth who suffer from mental illness.

“Solitary confinement can be dangerous, and a serious impediment to the ability of juveniles to succeed once released,” Holder said in a video statement, posted to the Justice Department’s website. “At a minimum, we must work to curb the overreliance on seclusion of youth with disabilities.”

Holder cites a 2012 study by the Justice Department’s Office of Juvenile Justice and Delinquency Prevention finding that nearly half, 47 percent to be precise, of the nation’s juvenile facilities lock youth in isolation. Another report from the same office found that more than one-third of youth in custody reported being isolated, with 55 percent saying it was longer than twenty-four hours.

“This practice is particularly detrimental to young people with disabilities—who are at increased risk under these circumstances of negative effects including self-harm and even suicide,” Holder said. “In fact, one national study found that half of the victims of suicides in juvenile facilities were in isolation at the time they took their own lives, and 62 percent of victims had a history of solitary confinement.”

Juan E. Méndez, the United Nations Special Rapporteur on Torture, said last year that solitary confinement can amount to torture and called for an “absolute ban” on the practice for juveniles and people battling disabilities.

Holder’s statement comes two months after the DOJ’s Civil Rights Division sought a court order to prevent Ohio’s juvenile corrections system from unlawfully isolating youth with mental illness. The DOJ’s request reported that the state had sent more than 229 boys with mental health needs to seclusion for a total of almost 66,000 hours. One boy spent nearly 2,000 hours in seclusion, while another was isolated for twenty-one straight days. In February, the DOJ criticized a juvenile facility in Contra County, California, for overzealously using solitary confinement.

Watch Holder’s statement, via the National Juvenile Defender Center: