Despite the recognised importance of mental disorders and social disconnectedness for mortality, few studies have examined their co-occurrence.

To examine the interaction between mental disorders and three distinct aspects of social disconnectedness on mortality, while taking into account sex, age and characteristics of the mental disorder.

This cohort study included participants from the Danish National Health Survey in 2013 and 2017 who were followed until 2021. Survey data on social disconnectedness (loneliness, social isolation and low social support) were linked with register data on hospital-diagnosed mental disorders and mortality. Poisson regression was applied to estimate independent and joint associations with mortality, interaction contrasts and attributable proportions.

A total of 162 497 individuals were followed for 886 614 person-years, and 9047 individuals (5.6%) died during follow-up. Among men, interaction between mental disorders and loneliness, social isolation and low social support, respectively, accounted for 47% (95% CI: 21–74%), 24% (95% CI: −15 to 63%) and 61% (95% CI: 35–86%) of the excess mortality after adjustment for demographics, country of birth, somatic morbidity, educational level, income and wealth. In contrast, among women, no excess mortality could be attributed to interaction. No clear trends were identified according to age or characteristics of the mental disorder.

Mortality among men, but not women, with a co-occurring mental disorder and social disconnectedness was substantially elevated compared with what was expected. Awareness of elevated mortality rates among socially disconnected men with mental disorders could be of importance to qualify and guide prevention efforts in psychiatric services.

尽管人们认识到精神障碍和社会脱节对死亡率的重要性，但很少有研究探讨它们的同时发生。

研究精神障碍与社会脱节对死亡率的三个不同方面之间的相互作用，同时考虑到性别、年龄和精神障碍的特征。

这项队列研究纳入了 2013 年和 2017 年丹麦国家健康调查的参与者，他们的随访一直持续到 2021 年。有关社会脱节（孤独、社会孤立和低社会支持）的调查数据与医院诊断的精神障碍和死亡率的登记数据相关联。应用泊松回归来估计与死亡率、交互对比和归因比例的独立和联合关联。

总共对 162 497 人进行了 886 614 人年的随访，其中 9047 人（5.6%）在随访期间死亡。在男性中，精神障碍与孤独、社会孤立和低社会支持之间的相互作用分别占 47%（95% CI：21-74%）、24%（95% CI：-15 至 63%）和 61% (95% CI: 35–86%) 调整人口统计数据、出生国、躯体发病率、教育水平、收入和财富后的超额死亡率。相比之下，在女性中，死亡率过高不能归因于相互作用。根据精神障碍的年龄或特征，没有发现明显的趋势。

与预期相比，同时存在精神障碍和社会脱节的男性死亡率大幅升高，而女性则不然。认识到与社会脱节的精神障碍男性死亡率升高对于确定和指导精神科服务的预防工作可能非常重要。