A guard tower looms over a federal prison complex which houses a Supermax facility outside Florence, in southern Colorado. 

Brennan Linsley/AP

One severely mentally ill inmate at ADX Florence, the federal supermax prison southwest of Colorado Springs, spent 19 years in isolation before being transferred to another facility. A new federal report says  the federal Bureau of Prisons disproportionately uses solitary confinement for inmates who are mentally ill, and that the inmates don't get the psychological treatment they need.

Inspector General Michael Horowitz told Colorado Matters that mentally ill inmates at ADX spend an average of nearly six years in solitary confinement, even though the bureau claims not to use the practice at all. It also says inmates aren't getting the psychological treatment they need.