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 == torture of imprisonment victims == 

 This article needs some mention of sleep deprivation used to torture victims of imprisonment. I believe that is the most widely used intentional application of sleep deprivation. I don't know where to find documentation of this suitable for publication here, but I have some clues:  

 * I saw a documentary that mentioned a 1600's swedish prison schedule that had the prisoners being awakened at 4 AM for breakfast and then being allowed to sleep at about 11 or 12 PM, leaving only a few hours of sleep on a prolonged basis. That's the oldest mention I know of off the top of my head of institutionalized torture using sleep deprivation.  

 * In modern imprisonment facilities, the same thing occurs as in the ancient swedish prison schedule: only a few hours each day are scheduled for prisoner sleep. In addition to the ancient methods, modern prisons also institute regular ""head counts"" where a prisoner is required to rise from bed and state his name to passing guards. 

 * Bed checks, cell checks, or just ""the rounds"" are where a guard is sent to personally look into prisoner cells every 5 to 20 minutes. This is done 24 hours a day, and guards frequently kick and rattle or slam the doors, yell at prisoners, yell to each other, sing songs, or otherwise interrupt a prisoner's already short sleep period. 

 * Unnaturally hard beds, harder than even earth or wild grasses, keeps prisoners from sleeping due to discomfort. 

 * Keeping prisoners irritable enlivens boring prison jobs and gives riot suppression teams something to do when prisoners lose the ability to think clearly and make good judgements, which often turns ordinary people into potentially violent ones.  

 * Prisoners who are already mentally ill go from being public nuisances to being raving loonies while deprived of sleep in the prisons. Even ordinary people will begin to hallucinate, leading to charges of insubordination or other misbehavior that the victim would not do without being sleep deprived. 

 * Permanent brain damage causes personality changes universally perceived as negative by those close to imprisonment survivors. Subsequent health problems, including psychological issues like PTSD and depression, are considered contributing factors of recidivism."