He missed ...

He missed people terribly, especially his fiancée and his family. He was despondent and depressed. Then, with time, he began to feel something more. He felt himself disintegrating. It was as if his brain were grinding down. A month into his confinement, he recalled in his memoir, “The mind is a blank. Jesus, I always thought I was smart. Where are all the things I learned, the books I read, the poems I memorized? There’s nothing there, just a formless, gray-black misery. My mind’s gone dead. God, help me.”

Is long-term solitary confinement torture? : The New Yorker

A powerful article for both the psychology and political information. You should also read Glenn Greenwald’s article about Bradley Manning’s situation, which gives some upsetting insights into the more recent politics of solitary confinement.