Risk factors for suicide in adults: systematic review and meta-analysis of psychological autopsy studies.

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.