Intensive use of forensic inpatient services by people with intellectual and developmental disabilities in Ontario, Canada: prevalence and associated characteristics

People with intellectual/developmental disabilities (IDD) are reportedly intensive users of forensic inpatient services. Using administrative data, we identified people with and without IDD in forensic inpatient settings in Ontario, Canada over a ten-year period. We compared them on sociodemographic, clinical, and admission characteristics and post-discharge healthcare use to explore factors that could account for differences in forensic inpatient resource use. The prevalence of IDD in forensic inpatient settings was 16.7% (vs. 0.8% population prevalence). Those with IDD did use forensic inpatient services more intensively (more historical forensic admissions, longer lengths of stay, greater staff frustration). There were, however, few differences between forensic inpatients with and without IDD in their baseline sociodemographics, upon admission, during their index forensic episode, or in accessing post-discharge healthcare services. The only differences were that those with IDD had higher percentages of forensic inpatient episodes under review board (ORB) supervision and of delayed discharge from hospital in the year post-forensic-discharge. These findings are more consistent with system-level than individual-level explanations and suggest that increasing forensic inpatient and community-based resources for individuals with IDD may be critical for reducing the intensity of their forensic inpatient use and increasing the likelihood of successful transition to the community.