Background

People in prison have an extremely high risk of suicide. The aim of this paper is to describe all suicides in the Norwegian prison population from 2000 to 2016, during and following imprisonment; to investigate the timing of suicides; and to investigate the associations between risk of suicide and types of crime.

Methods

We used data from the Norwegian Prison Release study (nPRIS) including complete national register data from the Norwegian Prison Register and the Norwegian Cause of Death Register in the period 1.1.2000 to 31.12.2016, consisting of 96,856 individuals. All suicides were classified according to ICD-10 codes X60-X84. We calculated crude mortality rates (CMRs) per 100,000 person-years and used a Cox Proportional-Hazards regression model to investigate factors associated with suicide during imprisonment and after release reported as hazard ratios (HRs).

Results

Suicide accounted for about 10% of all deaths in the Norwegian prison population and was the leading cause of death in prison (53% of in deaths in prison). The CMR per 100,000 person years for in-prison suicides was 133.8 (CI 100.5–167.1) and was ten times higher (CMR = 1535.0, CI 397.9–2672.2) on day one of incarceration. Suicides after release (overall CMR = 82.8, CI 100.5–167.1) also peaked on day one after release (CMR = 665.7, CI 0–1419.1). Suicide in prison was strongly associated with convictions of homicide (HR 18.2, CI 6.5–50.8) and high-security prison level (HR 15.4, CI 3.6–65.0). Suicide after release was associated with convictions of homicide (HR 3.1, CI 1.7–5.5).

Conclusion

There is a high risk of suicide during the immediate first period of incarceration and after release. Convictions for severe violent crime, especially homicide, are associated with increased suicide risk, both in prison and after release.

中文翻译：

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监狱自杀和释放后自杀：一项为期 17 年的全国队列研究

背景

监狱中的人有极高的自杀风险。本文的目的是描述 2000 年至 2016 年挪威监狱人口在监禁期间和之后的所有自杀事件；调查自杀的时间；并调查自杀风险与犯罪类型之间的关联。

方法

我们使用了挪威监狱释放研究 (nPRIS) 的数据，包括挪威监狱登记处和挪威死因登记处在 2000 年 1 月 1 日至 2016 年 12 月 31 日期间的完整国家登记数据，包括 96,856 人。所有自杀均根据 ICD-10 代码 X60-X84 进行分类。我们计算了每 100,000 人年的粗死亡率 (CMR)，并使用 Cox Proportional-Hazards 回归模型来调查与监禁期间和释放后自杀相关的因素，报告为风险比 (HR)。

结果

自杀约占挪威监狱人口死亡总数的 10%，是监狱死亡的主要原因（占监狱死亡人数的 53%）。监狱内自杀的每 100,000 人年的 CMR 为 133.8 (CI 100.5–167.1)，在监禁的第一天高出十倍 (CMR = 1535.0, CI 397.9–2672.2)。释放后的自杀（总体 CMR = 82.8，CI 100.5–167.1）也在释放后的第一天达到峰值（CMR = 665.7，CI 0–1419.1）。狱中自杀与杀人罪（HR 18.2，CI 6.5-50.8）和高安全监狱级别（HR 15.4，CI 3.6-65.0）密切相关。释放后自杀与杀人罪有关（HR 3.1，CI 1.7-5.5）。

结论

在监禁的第一阶段和释放后，自杀的风险很高。对严重暴力犯罪，尤其是凶杀案的定罪与监狱中和释放后的自杀风险增加有关。