The prevalence and comorbidity of mental health and substance use disorders in Scandinavian prisons 2010-2019: a multi-national register study.

BACKGROUND: Mental health disorders are common among people in prison, but their prevalence in the Scandinavian prison population remain unclear. In this multinational register study, we examined the prevalence of mental health disorders and the comorbidity of substance use disorders (SUDs) with other mental health disorders in this population. Further, we investigated how the prevalence of mental disorders at prison entry had changed in Norway, Denmark, and Sweden over the study period. METHODS: The three study cohorts included all individuals, aged 19 or older, whom had been imprisoned in Norway (2010-2019), Denmark (2011-2018), and Sweden (2010-2013). Mental disorders were defined as ICD-10 diagnoses (F-codes) registered in the national patient registers. The study prevalence was estimated based on recorded diagnoses during the entire study follow-up period in each respective country. The one-year prevalence of mental disorders was estimated for each calendar year for individuals entering prison during that year. RESULTS: The Scandinavian prison cohorts included 119 507 individuals released 191 549 times during the study period. Across all three countries a high proportion of both women (61.3%-74.4%) and men (49.6%-57.9%) had at least one mental health disorder during the observation period. The most prevalent disorders were SUDs (39.1%-44.0%), depressive disorder (8.1%-17.5%), and stress related disorder (8.8%-17.1%). Women (31.8%-41.1%) had higher levels of mental health and substance use comorbidities compared to men (20.8%-27.6%). The one-year prevalence of any mental health disorder increased over time with a 33% relative increase in Norway, 8% in Denmark, and 10% in Sweden. The proportion of individuals entering prison with a comorbid SUD and other mental disorder had also increased. CONCLUSIONS: While the incarceration rate has been decreasing during the past decade in the Scandinavian countries, an increasing proportion of people entering prison have a diagnosed mental health disorder. Our results suggest that prisons should provide adequate treatment and scale up services to accommodate the increasing proportion of people with complex health needs among incarcerated people.

The prevalence of substance use disorders among people in Norwegian, Danish and Swedish prisons: A multi-national cohort study, 2010-19.

AIMS: We estimated the prevalence of substance use disorders (SUDs) in the Norwegian, Danish and Swedish prison populations and compared the prevalence of SUDs in the national prison populations with country-specific general population prevalence rates. DESIGN: A multi-national cohort study using data from the National Prison Registries linked to the National Patient Registries in Norway, Denmark and Sweden. SETTING AND PARTICIPANTS: We used data from the PriSUD-Nordic study, including national prison populations aged 19 years and older in Norway (2010-19), Denmark (2010-18) and Sweden (2010-13). A total of 119 507 Individuals (108 971 men and 10 536 women) contributing to 191 549 incarcerations were included in the study (Norway: 45432 men; 5429 women, Denmark: 42 162 men; 3370 women, Sweden: 21 377 men; 1737 women). MEASUREMENT: We calculated a study prevalence and prevalence at entry to prison for all types of SUDs before imprisonment each consecutive year of observation in each prison population. We also extracted country-specific 1-year prevalence rates from the Global Burden of Diseases database to calculate comparative national prevalence ratios. FINDINGS: The study prevalence of any SUD was approximately 40% [Norway: 44.0%, 95% confidence interval (CI) = 43.6-44.5%; Denmark: 39.9%, CI = 39.5-40.4%; Sweden: 39.1%, CI = 38.4-39.7%] in all three countries. Women had a significantly higher study prevalence of any SUD compared with men (Norway: 55.8 versus 42.6%, P < 0.001; Denmark 43.1 versus 39.7%, P = 0.004; Sweden: 51.7 versus 38.0%, P < 0.001). Prevalence estimates were higher for SUDs among people in prison than in the general population. We observed an increasing proportion of people with SUDs entering prison in Norway (P = 0.003), while the proportion was more stable in Denmark and Sweden. CONCLUSIONS: Substance use disorders (SUDs) appear to be highly prevalent among the Scandinavian prison populations compared with the general population, especially among women. In Norway, there was a relative increase in SUDs from 2010 to 2019.