Background: Both the frequency of court-ordered treatments (COT) for offenders and prevalence of mental disorders among regular prison inmates steadily increased in most western countries. Whether there are major sociodemographic and clinical differences between these two populations is still matter of debate.

Methods: We compared the sociodemographic and clinical characteristics in a representative sample of 139 regular prison inmates versus 61 offenders with COT admitted during a 5-year period in an acute psychiatric care unit located in the central prison of the Geneva county. Fisher exact, unpaired Student's t and Mann-Whitney U tests were used to compare demographic and clinical variables between COT patients and regular inmates. In addition, univariate and multivariable ordered logistic regression models were built to identify the sociodemographic and clinical determinants of COT.

Results: COT patients were significantly older, less frequently married, with better education attainment, predominantly French-speaking, of the Christian religious group and with regular religious practice. History of psychiatric outpatient care was significantly more frequent in this group. Unlike the significantly higher occurrence of adjustment disorders in regular prisoners, psychosis was the main diagnosis in COT patients. When all diagnostic categories were taken into account in multivariable models, the presence of personality and psychotic disorders were the stronger predictors of COT status.

Conclusions: Our data reveal that offenders with COT represent a clinically distinct group with an overrepresentation of personality and psychotic disorders. Moreover, they show that, at least in the Swiss penitentiary system, COT patients are less exposed to acculturation issues compared to regular inmates.