When Lionel Penrose published his study, “Mental Disease and Crime: Outline of a Comparative Study of European Statistics”1 75 years ago, he had no way of knowing that his research would still be the subject of interest, and even controversy, in major psychiatric journals 3 quarters of a century later.2 Penrose found an inverse relationship between prison and mental hospital populations. He theorized that if one of these forms of confinement is reduced, the other will increase. According to this theory, where prison populations are extensive, mental hospital populations will be small, and vice versa. Writing before the advent of full-scale deinstitutionalization, Penrose could not have known that, in time, his hypothesis would be criticized by those who believe that there is no relationship between deinstitutionalization and criminalization of persons with serious mental illness and would be cited by those who believe that there is.
Lamb HR. Does Deinstitutionalization Cause Criminalization?The Penrose Hypothesis. JAMA Psychiatry. 2015;72(2):105-106. doi:10.1001/jamapsychiatry.2014.2444