The New York Times is reporting about 300 immigrants are being held in solitary confinement at U.S. detention centers on any given day even though they are being held on civil, not criminal, charges.

The Times reports nearly half are isolated for 15 days or more, the point at which psychiatric experts say they are at risk for severe mental harm. One Mexican immigrant says he was held in solitary for four months. He told the Times he sank into a deep depression as he overheard three other immigrant detainees attempt suicide.