WASHINGTON (AP) — The nation's federal prisons are holding inmates in solitary confinement for long periods of time, sometimes years, in spite of mounting evidence that it can seriously hurt their mental health, a government watchdog said Wednesday.

The Bureau of Prisons says it doesn't practice solitary confinement, or even recognize the term. But the Justice Department's inspector general found some inmates, including those with serious mental illness, languishing for years alone in their cells. At the Supermax prison in southern Colorado, for example, a pair of inmates were isolated in thei...