Alone in the dark

"What happens if you are left alone in the dark in solitary confinement for days on end? The result is called sensory deprivation and the human mind struggles to cope with it."

http://news.bbc.co.uk/1/hi/magazine/7199769.stm

"The nothingness, that was extremely hard. Because the question in your head is how am I going to get through the next 10 minutes? Or months later, how am I going to get through the next day? Is there enough left in my head?"