Question Effective prevention of suicide requires a comprehensive understanding of risk factors. Study selection and analysis Five databases were systematically searched to identify psychological autopsy studies (published up to February 2022) that reported on risk factors for suicide mortality among adults in the general population. Effect sizes were pooled as odds ratios (ORs) using random-effects models for each risk factor examined in at least three independent samples. Findings A total of 37 case–control studies from 23 countries were included, providing data on 40 risk factors in 5633 cases and 7101 controls. The magnitude of effect sizes varied substantially both between and within risk factor domains. Clinical factors had the strongest associations with suicide, including any mental disorder (OR=13.1, 95% CI 9.9 to 17.4) and a history of self-harm (OR=10.1, 95% CI 6.6 to 15.6). By comparison, effect sizes were smaller for other domains relating to sociodemographic status, family history, and adverse life events (OR range 2–5). Conclusions A wide range of predisposing and precipitating factors are associated with suicide among adults in the general population, but with clear differences in their relative strength. PROSPERO registration number CRD42021232878.

Self-harm is a leading cause of morbidity in prisoners. Although a wide range of risk factors for self-harm in prisoners has been identified, the strength and consistency of effect sizes is uncertain. We aimed to synthesise evidence and assess the risk factors associated with self-harm inside prison. In this systematic review and meta-analysis, we searched four electronic databases (PubMed, Embase, Web of Science, and PsycINFO) for observational studies on risk factors for self-harm in prisoners published from database inception to Oct 31, 2019, supplemented through correspondence with authors of studies. We included primary studies involving adults sampled from general prison populations who self-harmed in prison and a comparison group without self-harm in prison. We excluded studies with qualitative or ecological designs, those that reported on lifetime measures of self-harm or on selected samples of prisoners, and those with a comparison group that was not appropriate or not based on general prison populations. Data were extracted from the articles and requested from study authors. Our primary outcome was the risk of self-harm for risk factors in prisoners. We pooled effect sizes as odds ratios (OR) using random effects models for each risk factor examined in at least three distinct samples. We assessed study quality on the basis of the Newcastle-Ottawa Scale and examined between-study heterogeneity. The study protocol was registered with PROSPERO, CRD42018087915. We identified 35 independent studies from 20 countries comprising a total of 663 735 prisoners, of whom 24 978 (3·8%) had self-harmed in prison. Across the 40 risk factors examined, the strongest associations with self-harm in prison were found for suicide-related antecedents, including current or recent suicidal ideation (OR 13·8, 95% CI 8·6–22·1; I2=49%), lifetime history of suicidal ideation (8·9, 6·1–13·0; I2=56%), and previous self-harm (6·6, 5·3–8·3; I2=55%). Any current psychiatric diagnosis was also strongly associated with self-harm (8·1, 7·0–9·4; I2=0%), particularly major depression (9·3, 2·9–29·5; I2=91%) and borderline personality disorder (9·2, 3·7–22·5; I2=81%). Prison-specific environmental risk factors for self-harm included solitary confinement (5·6, 2·7–11·6; I2=98%), disciplinary infractions (3·5, 1·2–9·7; I2=99%), and experiencing sexual or physical victimisation while in prison (3·2, 2·1–4·8; I2=44%). Sociodemographic (OR range 1·5–2·5) and criminological (1·8–2·3) factors were only modestly associated with self-harm in prison. We did not find clear evidence of publication bias. The wide range of risk factors across clinical and custody-related domains underscores the need for a comprehensive, prison-wide approach towards preventing self-harm in prison. This approach should incorporate both population and targeted strategies, with multiagency collaboration between the services for mental health, social care, and criminal justice having a key role. Wellcome Trust.

Prisoners constitute a high-risk group for suicide. As an early stage in the pathway leading to suicide, suicidal ideation represents an important target for prevention, yet research on this topic is scarce in general prison populations. Using a cross-sectional survey design, correlates of suicidal ideation while incarcerated were examined in a sample of 1203 male prisoners, randomly selected from 15 Flemish prisons. Overall, a lifetime history of suicidal ideation and attempts was endorsed by 43.1% and 20.3% of respondents, respectively. Approximately a quarter of all prisoners (23.7%) reported past-year suicidal ideation during their current incarceration, which was significantly associated with both imported vulnerabilities (psychiatric diagnoses and a history of attempted suicide) and variables unique to the prison experience (lack of working activity, exposure to suicidal behaviour by peers, and low levels of perceived autonomy, safety and social support) in the multivariate regression analysis. A first-ever period of imprisonment and a shorter length of incarceration (≤12months) were also associated with increased odds of recent suicidal ideation. Collectively, the current findings underscore the importance of both vulnerability factors and prison-specific stressors for suicidal ideation in prisoners, and hence the need for a multi-faceted approach to suicide prevention in custodial settings. In addition to the provision of appropriate mental health care, environmental interventions that target modifiable aspects of the prison regime could provide a substantial buffer for the onset and persistence of suicidal ideation in this at-risk population.

Suicide is a global public health concern that affects all echelons of society, albeit not equally so. Compared with adults in the general population, incarcerated offenders are at increased risk to consider, attempt, and die by suicide, which represents a substantial burden of morbidity and mortality in prisons worldwide. This review synthesises recent literature pertaining to the epidemiology, risk factors, and prevention of suicidal thoughts and behaviour among prisoners, and outlines a framework which emphasises the interplay between individuals (importation) and their surroundings (deprivation). The available evidence suggests that prison-specific stressors may exacerbate risk of suicide in an already vulnerable population characterised by complex health and social care needs. Emerging data point to differential mechanisms through which prisoners come to think about suicide and subsequently progress to suicidal behaviour. As risk of suicide is determined by a complex web of synergistically interacting factors, its management and prevention demands a cross-sectoral policy and service response that includes targeted interventions aimed at high-risk prisoners in combination with population strategies that promote the health and wellbeing of all people in prison.