The triple burden experienced by incarcerated people in British Columbia: Mental illness, substance use, and poverty

Background: People transitioning from incarceration into the community often experience adverse health outcomes driven by the social determinants of health. This study aimed to compare the prevalence of mental health and substance use disorders and their associations with poverty and housing instability among people incarcerated in British Columbia provincial correctional centres versus the general community population.Methods: We used linked administrative data on a random 20% sample of BC residents enrolled in public health insurance. Individuals with any provincial incarceration in 2015 or 2021 were identified and compared with nonincarcerated individuals in those years. Prevalence of mental illness, substance use disorders, and indicators of social disadvantage (income assistance, no fixed address) were calculated for both groups. In 2021, the sample included 1933 incarcerated people and 962 421 nonincarcerated people.Results: Incarcerated people had significantly higher rates of mental illness and substance use disorder (including opioid and stimulant use disorders) than the community population. In 2021, 51.1% of incarcerated people had a diagnosed mental illness, 58.9% had a substance use disorder, and 41.0% had both. Co-occurring mental illness and substance use disorder were frequently associated with extreme poverty and housing instability. Nearly one-third (32.5%) of incarcerated people in 2021 had co-occurring mental illness and substance use disorder and either received income assistance or had no fixed address. Mental illness, substance use disorder, and poverty were much less common in the community cohort.Conclusions: Incarcerated people in BC experience a triple burden of mental illness, substance use disorders, and socioeconomic marginalization (poverty and homelessness). There is an urgent need for targeted interventions during incarceration (e.g., evidence-based mental health and substance use disorder treatment) and greater postrelease support (housing, social services, and employment opportunities) to reduce health inequities and break the cycle of recidivism.