title: Psychiatric Hospital Bed Numbers and Prison Population Sizes in 26 European Countries: A Critical Reconsideration of the Penrose Hypothesis.
abstract: BACKGROUND
  Recently, there has been a revived interest in the validity of the Penrose hypothesis, which was originally postulated over 75 years ago. It suggests an inverse relationship between the numbers of psychiatric hospital beds and the sizes of prison population. This study aims to investigate the association between psychiatric hospital beds and prison populations in a large sample of 26 European countries between 1993 and 2011.
  
  
  METHODS
  The association between prison population sizes and numbers of psychiatric hospital beds was assessed by means of Spearman correlations and modeled by a mixed random coefficient regression model. Socioeconomic variables were considered as covariates. Data were retrieved from Eurostat, the statistical office of the European Union.
  
  
  RESULTS
  Mean Spearman correlation coefficients between psychiatric beds and prison population showed a significant negative association (-0.35; p = <0.01). However, in the mixed regression model including socioeconomic covariates there were no significant fixed parameter estimates. Meanwhile, the covariance estimates for the random coefficients psychiatric beds (σ2 = 0.75, p = <0.01) and year (σ2 = 0.0007, p = 0.03) yielded significant results.
  
  
  CONCLUSIONS
  These findings do not support the general validity of the Penrose hypothesis. Notably, the results of the mixed-model show a significant variation in the magnitude and direction of the association of psychiatric hospital bed numbers and the prison population sizes between countries. In this sense, our results challenge the prevalent opinion that a reduction of psychiatric beds subsequently leads to increasing incarcerations. These findings also work against the potential stigmatization of individuals suffering from mental disorders as criminals, which could be an unintentional byproduct of the Penrose hypothesis.
authors.affiliation: Department of Psychoanalysis and Psychotherapy, Medical University of Vienna, Vienna, Austria.
authors.forename: Victor
authors.initials: V
authors.lastname: Blüml
authors.affiliation: Department of Epidemiology, Center of Public Health, Medical University of Vienna, Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Waldhör
authors.affiliation: Department of Psychoanalysis and Psychotherapy, Medical University of Vienna, Vienna, Austria.
authors.forename: Nestor D
authors.initials: ND
authors.lastname: Kapusta
authors.affiliation: Department of Psychiatry and Psychotherapy, Clinical Division of Social-Psychiatry, Medical University of Vienna, Vienna, Austria.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Vyssoki
mesh_terms: D005060:Europe; D005062:European Union; D006778:Hospitals, Psychiatric; D008962:Models, Theoretical; D011330:Prisons