Dealing With Dementia Among Aging Criminals - NYTimes.com: Dementia in prison is an underreported but fast-growing phenomenon, one that many prisons are desperately unprepared to handle. It is an unforeseen consequence of get-tough-on-crime policies — long sentences that have created a large population of aging prisoners. About 10 percent of the 1.6 million inmates in America’s prisons are serving life sentences; another 11 percent are serving over 20 years.