Homelessness is associated with adverse health and social outcomes. People experiencing homelessness have been found to have a high risk of violent crime victimisation as well as high prevalence of psychiatric disorders. It is poorly understood whether experiencing homelessness is associated with additional risks of violent offending and whether psychiatric disorders contribute to these risks. We examined the association between homelessness, psychiatric disorders, and first violence offence leading to conviction. We did a nationwide, register-based cohort study of all Danish residents who were alive at least 1 day during the study period, born between Jan 1, 1980, and Dec 31, 2006, and aged 15 years or older retrieved from the Danish Civil Registration System, which was linked to registers with information on homelessness, health care, and criminality. The exposure was any experience of homelessness, which was defined as having at least one contact with a homeless shelter during the study period. The outcome was first violent offence leading to a conviction. We calculated incidence rates per 10 000 person-years, incidence rate ratios (IRRs) using Poisson regression analysis, and probability of conviction of a violent offence using an Aalen–Johansen estimator. Analyses were stratified by sex and adjusted for calendar year of the study period, age, other sociodemographic factors, and psychiatric disorders. The study cohort included 1 786 433 Danish residents aged 15–42 years living in Denmark at some point from Jan 1, 2001, to Dec 31, 2021, contributing to 21 336 322 person-years at risk, of whom 57 084 (3·2%) individuals had their first violent offence leading to conviction during follow-up. 10 years after their first contact with a homeless shelter, 22·9% (95% CI 21·6–24·2) of men and 7·7% (6·8–8·7) of women had committed at least one violent crime leading to conviction. The fully adjusted IRRs of a violent offence leading to conviction were 4·8 (4·5–5·1) in men and 6·3 (5·6–7·2) in women experiencing homelessness compared with individuals who had not experienced homelessness. The IRR for a violent offence leading to conviction was highest in individuals experiencing homelessness and having co-occurring psychiatric disorders compared with those not experiencing homelessness and without co-occurring psychiatric disorders, especially drug use disorders (IRR in those experiencing homelessness and having a drug use disorder: 15·3 [14·1–16·7] in men and 40·1 [33·9–47·5] in women compared with individuals not experiencing homelessness and having no drug use disorder). Individuals experiencing homelessness had higher risks of a violent offence leading to conviction than those who had not experienced homelessness. In addition to preventing homelessness, public health and policy should consider how to reduce the risk of adverse outcomes in people experiencing homelessness. Lundbeck Foundation.

中文翻译：

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丹麦的无家可归、精神疾病和暴力：一项基于人群的队列研究


无家可归与不良的健康和社会后果有关。研究发现，无家可归者遭受暴力犯罪侵害的风险很高，精神疾病的患病率也很高。人们对无家可归是否与暴力犯罪的额外风险相关以及精神疾病是否会导致这些风险知之甚少。我们研究了无家可归、精神疾病和首次定罪的暴力犯罪之间的关联。我们对所有在研究期间存活至少 1 天、出生于 1980 年 1 月 1 日至 2006 年 12 月 31 日之间、年龄在 15 岁或以上的丹麦居民进行了一项全国性的、基于登记的队列研究，这些居民是从丹麦公民数据库检索的。登记系统，与无家可归、医疗保健和犯罪信息的登记册相连。暴露是指任何无家可归的经历，其定义为在研究​​期间至少与无家可归者收容所有过一次接触。结果是第一次暴力犯罪被定罪。我们使用泊松回归分析计算了每万人年的发病率、发病率比 (IRR)，并使用 Aalen-Johansen 估计量计算了暴力犯罪的定罪概率。分析按性别分层，并根据研究期间的日历年份、年龄、其他社会人口因素和精神疾病进行调整。该研究队列包括2001年1月1日至2021年12月31日期间居住在丹麦的1 786 433名年龄在15至42岁之间的丹麦居民，导致21 336 322人年面临风险，其中57 084人（3· 2%）个人首次发生暴力犯罪，并在后续过程中被定罪。 第一次接触无家可归者收容所 10 年后，22·9% (95% CI 21·6–24·2) 的男性和 7·7% (6·8–8·7) 的女性至少犯过一次导致定罪的暴力犯罪。与没有经历过无家可归的个人相比，导致定罪的暴力犯罪的完全调整 IRR 在男性中为 4·8 (4·5–5·1)，在经历过无家可归的女性中为 6·3 (5·6–7·2)无家可归。与那些没有经历过无家可归和没有同时发生精神疾病，特别是吸毒障碍的人相比，经历过无家可归和同时患有精神疾病的人，导致定罪的暴力犯罪的 IRR 最高（IRR 发生在无家可归和同时患有精神疾病的人中）使用障碍：与没有经历过无家可归和没有吸毒障碍的个体相比，男性为 15·3 [14·1–16·7]，女性为 40·1 [33·9–47·5]。与没有经历过无家可归的人相比，经历过无家可归的人因暴力犯罪而被定罪的风险更高。除了防止无家可归之外，公共卫生和政策还应考虑如何降低无家可归者出现不良后果的风险。灵北基金会。