The bidirectional association between psychiatric disorders and sheltered homelessness.

BACKGROUND: Psychiatric disorders and homelessness are related, but temporal associations are unclear. We aimed to explore the overlap between hospital-based psychiatric disorders and sheltered homelessness. METHODS: This population-based cohort study was conducted using the Danish registers e.g., the Danish Homeless Register and the Danish National Patient Register. The study cohort included all individuals aged 15 years or older, living in Denmark at least one day during 2002-2021 (born 1984-2006). First psychiatric diagnosis was used to define psychiatric disorder and first homeless shelter contact to define homelessness. Adjusted incidence rate ratios (IRRs) and cumulative incidences were estimated. RESULTS: Among 1 530 325 individuals accounting for 16 787 562 person-years at risk aged 15-38 years, 11 433 (0.8%) had at least one homeless shelter contact. Among 1 406 410 individuals accounting for 14 131 060 person-years at risk, 210 730 had at least one psychiatric disorder. People with any psychiatric disorder had increased risk of sheltered homelessness relative to individuals with no psychiatric disorder [IRR 9.2, 95% confidence interval (CI) 8.8-9.6]. Ten years after first psychiatric disorder, 3.0% (95% CI 2.9-3.1) had at least one homeless shelter contact. Individuals experiencing homelessness had increased risk of any psychiatric disorder compared to individuals with no homeless shelter contact (IRR 7.0, 95% CI 6.7-7.4). Ten years after first homeless shelter contact, 47.1% (45.3-48.0) had received a hospital-based psychiatric diagnosis. CONCLUSION: Strong bidirectional associations between psychiatric disorders and homelessness were identified. Health and social care professionals should be aware of and address these high risks of accumulated psychiatric and social problems.

Risk of homelessness after prison release and recidivism in Denmark: a nationwide, register-based cohort study.

BACKGROUND: Transitional periods between and across services have been linked to homelessness. We aimed to investigate the association of previous history of homelessness and psychiatric disorders with risk of homelessness after release from prison. Additionally, we examined the association between homelessness after release and risk of recidivism. METHODS: We did a nationwide, register-based cohort study of people aged 15 years or older who were released from prison for the first time in Denmark between Jan 1, 2001, and Dec 31, 2021. We obtained data using the Danish Civil Registration System with data linked across other registries (the Danish Central Criminal Register, the Danish Homeless Register, the Danish National Patient Register, and the Danish Psychiatric Central Research Register) on release date, homeless shelter contacts, psychiatric disorders, and new convictions. Outcomes were homelessness after release from prison, defined as first homeless shelter contact following release from first imprisonment, and recidivism within 2 years of release, defined as the first police-recorded criminal conviction after prison release. We calculated incidence rates per 1000 person-years, incidence rate ratios (IRRs) using Poisson regression analysis, and probability of homelessness and recidivism after release. Sex, age, calendar year, country of origin, highest educational level, relationship status, and length of index imprisonment were included as confounders. FINDINGS: The study cohort included 37 382 individuals (34 792 males [93·1%] and 2590 females [6·9%]) aged 15-41 years, who were released from prison between Jan 1, 2001, and Dec 31, 2021, contributing 202 197 person-years at risk. Mean follow-up duration was 5·4 person-years (SD 5·6). Overall, 1843 (4·9%) of 37 382 individuals became homeless. 1 year after release from prison, 788 (2·1%) of 37 382 individuals had at least one homeless shelter contact, and among 1761 individuals with previous history of homelessness before index imprisonment, 357 (20·7%) became homeless. The incidence of homelessness after release was 102·5 cases per 1000 person-years for individuals with previous history of homelessness and 6·7 cases per 1000 person-years in individuals without (IRR 16·4, 95% CI 14·8-18·2; adjusted for sex, age, and calendar year). Individuals who additionally had a mental illness had a higher risk of homelessness (IRR 22·6, 19·7-25·9) compared with those without either previous homelessness or mental illness, and a substantially higher risk was observed for those with previous homelessness and drug use disorder (25·0, 21·6-28·9) compared with those without. Within 2 years of release from prison, the probability of recidivism was 73·2% (95% CI 72·8-73·7). The risk of recidivism was higher among people experiencing homelessness after release from prison than those who did not experience homelessness after release (IRR 1·5, 95% CI 1·3-1·7), adjusted for sex, age, and calendar year. INTERPRETATION: Criminal justice services should review approaches to reduce risk of homelessness, and consider improving liaison with mental health and substance misuse services to prevent adverse outcomes on release from prison. Clinical guidelines applied to criminal justice settings should address the health of individuals who experience homelessness. FUNDING: Lundbeck Foundation.

Influence of vaccination on adverse health outcomes after SARS-CoV-2 infection among individuals with alcohol use disorder: a population-based study.

BACKGROUND AND AIMS: Alcohol use disorders (AUD) have not been included in the priority groups for early vaccine against SARS-CoV-2. We aimed to determine adverse outcomes after SARS-CoV-2 infection among individuals with AUD and how this is modified by vaccination. DESIGN, SETTING AND PARTICIPANTS: This was a registry-based cohort study carried out in Denmark, 27 February 2020 to 15 October 2021, comprising 2157 individuals with AUD and 237 541 without AUD who had had a polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection during the study period. MEASUREMENTS: The association of AUD with the absolute and relative risk of hospitalization, intensive care and 60-day mortality after SARS-CoV-2 infection and of all-cause mortality throughout the follow-up period were measured. Potential interactions with SARS-CoV-2 vaccination, education and sex were explored in stratified analyses and tested by including interaction terms and using likelihood ratio tests. FINDINGS: Individuals with AUD had an increased absolute and relative risk of adverse outcomes, including hospitalization [incidence rate ratio (IRR) = 1.72, 95% confidence interval (CI) = 1.51-1.95], intensive care (IRR = 1.47, 95% CI = 1.07-2.02) and 60-day mortality [mortality rate ratio (MRR) = 2.35, 95% CI = 1.94-2.85] compared with SARS-CoV-2-positive individuals without AUD. Irrespective of AUD, highest risks of these adverse health outcomes were observed for individuals not vaccinated against SARS-CoV-2 infection, for individuals of low educational level and in males. However, for all-cause mortality throughout the follow-up period, SARS-CoV-2 infection showed a lower relative mortality risk increase, whereas being unvaccinated showed a higher relative mortality risk increase, in individuals with AUD than in the reference population without AUD (P of interaction tests < 0.0001). CONCLUSIONS: Both alcohol use disorder and being unvaccinated for SARS-CoV-2 appear to be independent risk factors for adverse health outcomes following SARS-CoV-2 infection.

Clinical Recovery and Long-Term Association of Specialized Early Intervention Services vs Treatment as Usual Among Individuals With First-Episode Schizophrenia Spectrum Disorder: 20-Year Follow-up of the OPUS Trial.

Importance: The OPUS 20-year follow-up is the longest follow-up of a randomized clinical trial testing early intervention services (EIS) among individuals with first-episode schizophrenia spectrum disorder. Objective: To report on long-term associations of EIS compared with treatment as usual (TAU) for first-episode schizophrenia spectrum disorder. Design, Setting, and Participants: A total of 547 individuals were included in this Danish multicenter randomized clinical trial between January 1998 and December 2000 and allocated to early intervention program group (OPUS) or TAU. Raters who were blinded to the original treatment performed the 20-year follow-up. A population-based sample aged 18 to 45 years with first-episode schizophrenia spectrum disorder were included. Individuals were excluded if they were treated with antipsychotics (>12 weeks prior to randomization), had substance-induced psychosis, had mental disability, or had organic mental disorders. Analysis took place between December 2021 and August 2022. Interventions: EIS (OPUS) consisted of 2 years of assertive community treatment including social skill training, psychoeducation, and family involvement by a multidisciplinary team. TAU consisted of the available community mental health treatment. Main Outcomes and Measures: Psychopathological and functional outcomes, mortality, days of psychiatric hospitalizations, number of psychiatric outpatient contacts, use of supported housing/homeless shelters, symptom remission, and clinical recovery. Results: Of 547 participants, 164 (30%) were interviewed at 20-year follow-up (mean [SD] age, 45.9 [5.6] years; 85 [51.8%] female). No significant differences were found between the OPUS group compared with the TAU group on global functional levels (estimated mean difference, -3.72 [95% CI, -7.67 to 0.22]; P = .06), psychotic symptom dimensions (estimated mean difference, 0.14 [95% CI, -0.25 to 0.52]; P = .48), and negative symptom dimensions (estimated mean difference, 0.13 [95% CI, -0.18 to 0.44]; P = .41). The mortality rate was 13.1% (n = 36) in the OPUS group and 15.1% (n = 41) in the TAU group. Likewise, no differences were found 10 to 20 years after randomization between the OPUS and TAU groups on days of psychiatric hospitalizations (incidence rate ratio, 1.20 [95% CI, 0.73-1.20]; P = .46) or number of outpatient contacts (incidence rate ratio, 1.20 [95% CI, 0.89-1.61]; P = .24). Of the entire sample, 53 participants (40%) were in symptom remission and 23 (18%) were in clinical recovery. Conclusions and Relevance: In this follow-up study of a randomized clinical trial, no differences between 2 years of EIS vs TAU among individuals with diagnosed schizophrenia spectrum disorders at 20 years were found. New initiatives are needed to maintain the positive outcomes achieved after 2 years of EIS and furthermore improve very long-term outcomes. While registry data was without attrition, interpretation of clinical assessments are limited by high attrition rate. However, this attrition bias most likely confirms the lack of an observed long-term association of OPUS with outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT00157313.

Association between SARS-CoV-2 infection and self-harm: Danish nationwide register-based cohort study.

BACKGROUND: Case studies have linked SARS-CoV-2 infection to suicidal behaviour. However, conclusive evidence is lacking. AIMS: To examine whether a history of SARS-CoV-2 infection or SARS-CoV-2-related hospital admission was associated with self-harm in the general population and in high-risk groups. METHOD: A cohort design was applied to nationwide data on all people aged ≥15 years and living in Denmark between 27 February 2020 and 15 October 2021. Exposure was identified as having had a positive SARS-CoV-2 PCR test, and further assessed as SARS-CoV-2-related hospital admission. Rates of probable self-harm were examined using adjusted incidence rate ratios (aIRRs). The following subgroups were identified: (a) lower educational level, (b) chronic medical conditions, (c) disability pension, (d) mental disorders, (e) substance use disorders, and history of (f) homelessness and (g) imprisonment. RESULTS: Among 4 412 248 included individuals, 260 663 (5.9%) had tested positive for SARS-CoV-2. Out of 5453 individuals presenting with self-harm, 131 (2.4%) had been infected. Individuals with a history of a positive SARS-CoV-2 test result had an aIRR for self-harm of 0.86 (95% CI 0.72-1.03) compared with those without. High rates were found after a SARS-CoV-2-related hospital admission (aIRR = 7.68; 95% CI 5.61-10.51) or a non-SARS-CoV-2-related admission (aIRR = 10.27; 95% CI 9.65-10.93) versus non-infected and not admitted. In sensitivity analyses with a more restrictive definition of self-harm, a positive PCR test was associated with lower rates of self-harm. CONCLUSIONS: Individuals with a PCR-confirmed SARS-CoV-2 infection did not have higher rates of self-harm than those without. Hospital admission in general, rather than being SARS-CoV-2 positive. seemed to be linked to elevated rates of self-harm.

Adverse SARS-CoV-2-associated outcomes among people experiencing social marginalisation and psychiatric vulnerability: A population-based cohort study among 4,4 million people.

Background: Knowledge of the adverse problems related to SARS-CoV-2 infection in marginalised and deprived groups may help to prioritise more preventive efforts in these groups. We examined adverse outcomes associated with SARS-CoV-2 infection among vulnerable segments of society. Methods: Using health and administrative registers, a population-based cohort study of 4.4 million Danes aged at least 15 years from 27 February 2020 to 15 October 2021 was performed. People with 1) low educational level, 2) homelessness, 3) imprisonment, 4) substance abuse, 5) supported psychiatric housing, 6) psychiatric admission, and 7) severe mental illness were main exposure groups. Chronic medical conditions were included for comparison. COVID-19-related outcomes were: 1) hospitalisation, 2) intensive care, 3) 60-day mortality, and 4) overall mortality. PCR-confirmed SARS-CoV-2 infection and PCR-testing were also studied. Poisson regression analysis was used to compute adjusted incidence and mortality rate ratios (IRRs, MRRs). Findings: Using health and administrative registers, we performed a population-based cohort study of 4,412,382 individuals (mean age 48 years; 51% females). In all, 257,450 (5·8%) individuals had a PCR-confirmed SARS-CoV-2 infection. After adjustment for age, calendar time, and sex, we found that especially people experiencing homelessness had high risk of hospitalisation (IRR 4·36, 95% CI, 3·09-6·14), intensive care (IRR 3·12, 95% CI 1·29-7·52), and death (MRR 8·17, 95% CI, 3·66-18·25) compared with people without such experiences, but increased risk was found for all studied groups. Furthermore, after full adjustment, including for status of vaccination against SARS-CoV-2 infection, individuals with experiences of homelessness and a PCR-confirmed SARS-CoV-2 infection had 41-times (95% CI, 24·84-68·44) higher risk of all-cause death during the study period compared with individuals without. Supported psychiatric housing was linked to almost 3-times higher risk of hospitalisation and 60-day mortality following SARS-CoV-2 infection compared with the general population with other living circumstances. Interpretation: Socially marginalised and psychiatrically vulnerable individuals had substantially elevated risks of adverse health outcomes following SARS-CoV-2 infection. The results highlight that pandemic preparedness should address inequalities in health, including infection prevention and vaccination of vulnerable groups. Funding: Novo Nordisk Foundation.

Vaccination against SARS-CoV-2 infection among vulnerable and marginalised population groups in Denmark: A nationwide population-based study.

Background: Social deprivation, psychiatric and medical disorders have been associated with increased risk of infection and severe COVID-19-related health problems. We aimed to study the rates of SARS-CoV-2 vaccination in these high-risk groups. Methods: Using health, vaccination, and administrative registers, we performed a population-based cohort study including all Danish residents aged at least 15 years, December 27, 2020, to October 15, 2021. Population groups were people experiencing: (1) homelessness, (2) imprisonment, (3) substance abuse, (4) severe mental illness, (5) supported psychiatric housing, (6) psychiatric admission, and (7) chronic medical condition. The outcome was vaccine uptake of two doses against SARS-CoV-2 infection. We calculated cumulative vaccine uptake and adjusted vaccination incidence rate ratios (IRRs) relative to the general population by sex and population group. Findings: The cohort included 4,935,344 individuals, of whom 4,277,380 (86·7%) received two doses of vaccine. Lower cumulative vaccine uptake was found for all socially deprived and psychiatrically vulnerable population groups compared with the general population. Lowest uptake was found for people below 65 years experiencing homelessness (54·6%, 95% confidence interval (CI) 53·4-55·8, p<0·0001). After adjustment for age and calendar time, homelessness was associated with markedly lower rates of vaccine uptake (IRR 0·5, 95% CI 0·5-0·6 in males and 0·4, 0·4-0·5 in females) with similar results for imprisonment. Lower vaccine uptake was also found for most of the psychiatric groups with the lower IRR for substance abuse (IRR 0·7, 0·7-0·7 in males and 0·8, 0·8-0·8 in females). Individuals with new-onset severe mental illness and, especially, those in supported psychiatric housing and with chronic medical conditions had the highest vaccine uptake among the studied population groups. Interpretation: Especially, socially deprived population groups, but also individuals with psychiatric vulnerability need higher priority in the implementation of the vaccination strategy to increase equity in immunization uptake. Funding: Novo Nordisk Foundation.

Homelessness and police-recorded crime victimisation: a nationwide, register-based cohort study.

BACKGROUND: Homelessness is associated with crime victimisation, which is a leading cause of death, exacerbates health problems, and increases the risk of violence. We aimed to study the risk of police-recorded crime victimisation in individuals with experiences of homelessness compared with the general population. METHODS: We did a nationwide, register-based cohort study of people aged 15 years or older, who were alive in 2001 and born in Denmark between 1980 and 2001. The cohort was constructed using the Danish Civil Registration System, with data linked across other registries (including the Danish Homeless Register, Danish Psychiatric Central Research Register, and the Danish Central Crime Register) by use of personal identification numbers. The exposure, experience of homelessness, was defined as at least one contact with a homeless shelter. The outcome was the date of first police-recorded crime victimisation. We calculated incidence rates per 1000 person-years, incidence rate ratios (IRRs), and cumulative probability of any crime victimisation and of violent crime victimisation. Psychiatric disorders, socioeconomic markers, and history of criminal offences were included as confounders. FINDINGS: Within the study period (Jan 1, 2001, to Dec 31, 2015), 1 182 749 individuals (9 831 776 person-years) aged 15-35 years were included, of which 184 813 (15·6%) had at least one crime victimisation incident (73 999 [40%] of which were violent victimisations). 4286 individuals (22 240 person-years) had at least one homeless shelter contact. Relative to the general population, and adjusting for age and calendar year, individuals with experience of homelessness had an increased risk of any crime victimisation (IRR 2·7 [95% CI 2·4-3·0]) in females and 2·3 [2·1-2·5] in males), and especially of violent crime victimisation (7·2 [6·3-8·2] in females and 3·6 [3·2-4·0] in males). This increased risk remained significant after further adjustments for potential confounders. People with both a psychiatric diagnosis and experience of homelessness had the highest risk of violent victimisation (IRR 10·1 [95% CI 8·6-11·9] in females and 4·3 [3·8-4·9] in males), while people with no psychiatric diagnosis or experience of homelessness (the reference group) had the lowest risk. In the 5 years after an individual's first homeless shelter contact, the cumulative probabilities of any crime victimisation were 23% (95% CI 21-26) in females and 16% (15-18) in males, which were substantially higher than those of the general population. INTERPRETATION: Homeless populations are at substantially increased risk of crime victimisation, highlighting the need for strategic and targeted approaches to prevent homelessness and to help people out of homelessness. Improvements in multiagency working (such as between homeless shelters, health-care services, substance misuse services, and police forces) might be important to reduce the risk of victimisation in marginalised populations, such as those with complex psychiatric or social problems, with experience of homelessness. FUNDING: Lundbeck Foundation.

Individual-Level Predictors for Becoming Homeless and Exiting Homelessness: a Systematic Review and Meta-analysis.

Homelessness remains a societal problem. Compiled evidence of predictors for becoming homeless and exiting homelessness might be used to inform policy-makers and practitioners in their work to reduce homeless-related problems. We examined individual-level predictors for becoming homeless and exiting homelessness by searching PubMed, EMBASE, PsycINFO, and Web of Science up to January 2018. Becoming homeless and exiting homelessness were the outcomes. Observational studies with comparison groups from high-income countries were included. The Newcastle Ottawa Quality Assessment Scale was used for bias assessment. Random effects models were used to calculate pooled odds ratios (ORs) with 95% confidence intervals (CIs). We included 116 independent studies of risk factors for becoming homeless and 18 for exiting homelessness. We found evidence of adverse life events as risk factors for homelessness, e.g., physical abuse (OR 2.9, 95% CI 1.8-4.4) and foster care experiences (3.7, 1.9-7.3). History of incarceration (3.6, 1.3-10.4), suicide attempt (3.6, 2.1-6.3), and psychiatric problems, especially drug use problems (2.9, 1.5-5.1), were associated with increased risk of homelessness. The heterogeneity was substantial in most analyses (I2 > 90%). Female sex (1.5, 1.1-1.9; I2 = 69%) and having a partner (1.7, 1.3-2.1; I2 = 40%) predicted higher chances whereas relationship problems (0.6, 0.5-0.8), psychotic disorders (0.4, 0.2-0.8; I2 = 0%), and drug use problems (0.7, 0.6-0.9; I2 = 0%) reduced the chances for exiting homelessness. In conclusion, sociodemographic factors, adverse life events, criminal behaviour, and psychiatric problems were individual-level predictors for becoming homeless and/or exiting homelessness. Focus on individual-level vulnerabilities and early intervention is needed. PROSPERO registration number: CRD42014013119 .

Risk of psychiatric disorders in offspring of parents with a history of homelessness during childhood and adolescence in Denmark: a nationwide, register-based, cohort study.

BACKGROUND: Children and adolescents from deprived backgrounds have high rates of psychiatric problems. Parental and social factors are crucial for children's healthy and positive development, but whether psychiatric morbidity is associated with parental social marginalisation is unknown. We aimed to analyse the association between mother's and father's history of homelessness and the offspring's risk of psychiatric disorders, including substance use disorder, during childhood and adolescence. METHODS: We did a nationwide, register-based cohort study of 1 072 882 children and adolescents aged 0-16 years, who were living or born in Denmark between Jan 1, 1999, and Dec 31, 2015. Parental homelessness was the primary exposure, data on which were obtained from the Danish Homeless Register. The Danish Civil Registration System was used to extract the population and link offspring to parental information, and the outcome, psychiatric disorders in the offspring, was obtained from the Danish Psychiatric Central Research Register and the Danish National Patient Register. We analysed the association between parental history of homelessness and risk of psychiatric disorders in offspring by survival analysis using Poisson regression and incidence rate ratios (IRRs), adjusted for year and offspring characteristics, and additionally adjusted for parental factors (age at offspring's birth and parental psychiatric disorders). FINDINGS: 17 238 (2%) offspring had either one or two parents with a history of homelessness, and 56 330 (5%) children and adolescents were diagnosed with any psychiatric disorder during the study period. The incidence of any psychiatric disorder was 15·1 cases per 1000 person-years (95% CI 14·4-15·8) in offspring with at least one parent with a history of homelessness, compared with 6·0 per 1000 person-years (95% CI 6·0-6·1) in those whose parents had no such history (IRR 2·5 [95% CI 2·3-2·7] for mother homeless, 2·3 [2·2-2·5] for father homeless, and 2·8 [2·4-3·2] for both parents homeless, after adjustment for year and offspring characteristics). This risk remained elevated after additional adjustment for factors including parental psychiatric disorders. IRRs in offspring were increased for most specific psychiatric disorders, with the highest risk for attachment disorder when both parents had a history of homelessness (IRR 32·5 [95% CI 24·6-42·9]) and substance use disorder when only the mother had a history of homelessness (6·9 [4·9-9·7]). In offspring whose mothers had a history of both homelessness and a psychiatric disorder, 35·9% (95% CI 27·1-44·8) had been diagnosed with a psychiatric disorder by the age of 15 years. INTERPRETATION: Parental homelessness was associated with an increased risk of psychiatric disorders in offspring during childhood and adolescence. These findings have important implications for public health and policy because they suggest a need for improvement in the support of socially marginalised families to help prevent psychiatric illness in offspring. FUNDING: University of Copenhagen, The Lundbeck Foundation Initiative for Integrated Psychiatric Research (iPSYCH).