[Risk of incarceration of persons undergoing psychiatric care. A retrospective longitudinal study on the French department of Oise using information from a psychiatric hospital discharge database]

INTRODUCTION

Compared to the general population, persons with mental disorders are overrepresented in prison. In a study carried out in Picardy (northern France) in 2017, a quarter of those entering prison had had contact with a psychiatric service prior to their incarceration. Since to our knowledge no work on this subject has been published in France, we conducted a retrospective study, the main objective of which was to propose an estimate measure of incarceration likelihood in people with mental disorders.

METHODS

Using data from a psychiatric hospital discharge database (Recueil d'informations médicalisé en psychiatrie, RimP), we searched for patients aged 18 and older who had received psychiatric care (except for those who were incarcerated at baseline) at the Oise psychiatric hospital in 2015-2016 and identified those who had also been registered by the psychiatric care tool (DSP) in liaison with the same hospital. As a marker of incarceration, registration was the event to be investigated. Survival analyses (Kaplan-Meier), first simple and then stratified by age, gender, past history, main diagnosis and intensity of care outside of prison were carried out to calculate likelihood of incarceration. A multivariate Cox model was used in order to identify the factors associated with incarceration.

RESULTS

Among the 25,029 patients monitored in the Oise psychiatric hospital in 2015-2016, 126 had experienced incarceration during the 12 months following their inclusion in the study, i.e. an incarceration probability of 0.45% (95 % confidence interval: 0.37-0.55%). The incarcerated patients were younger (36.6 years in average versus 44.7-Pt-test<0.0001), more often male (96.8% versus 43.7% - P<0.0001), and had a more frequent history of detention (11.1% versus 0.6% - P <0.0001) and psychiatric care (20.6% versus 10.1% - P<0.0001) than the general population. The probability of incarceration at 12 months for the population followed in the psychiatry unit was 3.2 times higher than the detention rate of the general population in Oise over the same period.

CONCLUSION

Our study confirms the pronouncedly high incarceration rate of people with mental disorders. Scheduled to begin in 2020, coding in the RimP of a single nationwide patient identifier for all the procedures and stays described will allow the generalized measurement by means of the proposed indicator throughout France.