Human beings are social creatures. We are social not just in the trivial sense that we like company, and not just in the obvious sense that we each depend on others. We are social in a more elemental way: simply to exist as a normal human being requires interaction with other people.
In light of this, is depriving prisoners of human contact equivalent to torture? The State is depriving them of the tools they need to stay human. There are no physical scars, but just like regular torture which preys on humans' inherent reaction to pain, solitary confinement preys on humans' need for social interaction.
Further, is it any wonder that inmates -- dehumanized by solitary confinement -- go on to commit more crimes?
Are we as a society okay with the fact that we subject American inmates (not only "suspected terrorists") to something akin to torture? If so, shouldn't we get over the myth that our prisons are "correctional" facilities meant to rehabilitate prisoners? Should we get used to the idea that our prisons are meant for crude retribution only?