Age-specific suicide mortality following non-fatal self-harm: national cohort study in Sweden.

BACKGROUND: Possible age-related differences in risk of completed suicide following non-fatal self-harm remain unexplored. We examined associations between self-harm and completed suicide across age groups of self-harming patients, and whether these associations varied by violent index method, presence of mental disorder, and repeated self-harm. METHOD: The design was a cohort study with linked national registers in Sweden. The study population comprised individuals aged ⩾10 years hospitalized during 1990-1999 due to non-fatal self-harm (n = 53 843; 58% females) who were followed for 9-19 years. We computed hazard ratios (HRs) across age groups (age at index self-harm episode), with time to completed suicide as outcome. RESULTS: The 1-year HR for suicide among younger males (10-19 years) was 14.6 [95% confidence interval (CI) 4.1-51.9] for violent method and 8.4 (95% CI 1.8-40.0) for mental disorder. By contrast, none of the three potential risk factors increased the 1-year risks in the youngest females. Among patients aged ⩾20 years, the 1-year HR for violent method was 4.6 (95% CI 3.8-5.4) for males and 10.4 (95% CI 8.3-13.0) for females. HRs for repeated self-harm during years 2-9 of follow-up were higher in 10- to 19-year-olds (males: HR 4.0, 95% CI 2.0-7.8; females: HR 3.7, 95% CI 2.1-6.5). The ⩾20 years age groups had higher HRs than the youngest, particularly for females and especially within 1 year. CONCLUSIONS: Violent method and mental disorder increase the 1-year suicide risk in young male self-harm patients. Further, violent method increases suicide risk within 1 year in all age and gender groups except the youngest females. Repeated self-harm may increase the long-term risk more in young patients. These aspects should be accounted for in clinical suicide risk assessment.

Familial clustering of suicide risk: a total population study of 11.4 million individuals.

BACKGROUND: Research suggests that suicidal behaviour is aggregated in families. However, due to methodological limitations, including small sample sizes, the strength and pattern of this aggregation remains uncertain. METHOD: We examined the familial clustering of completed suicide in a Swedish total population sample. We linked the Cause of Death and Multi-Generation Registers and compared suicide rates among relatives of all 83 951 suicide decedents from 1952-2003 with those among relatives of population controls. RESULTS: Patterns of familial aggregation of suicide among relatives to suicide decedents suggested genetic influences on suicide risk; the risk among full siblings (odds ratio 3.1, 95% confidence interval 2.8-3.5, 50% genetic similarity) was higher than that for maternal half-siblings (1.7, 1.1-2.7, 25% genetic similarity), despite similar environmental exposure. Further, monozygotic twins (100% genetic similarity) had a higher risk than dizygotic twins (50% genetic similarity) and cousins (12.5% genetic similarity) had higher suicide risk than controls. Shared (familial) environmental influences were also indicated; siblings to suicide decedents had a higher risk than offspring (both 50% genetically identical but siblings having a more shared environment, 3.1, 2.8-3.5 v. 2.0, 1.9-2.2), and maternal half-siblings had a higher risk than paternal half-siblings (both 50% genetically identical but the former with a more shared environment). Although comparisons of twins and half-siblings had overlapping confidence intervals, they were supported by sensitivity analyses, also including suicide attempts. CONCLUSIONS: Familial clustering of suicide is primarily influenced by genetic and also shared environmental factors. The family history of suicide should be considered when assessing suicide risk in clinical settings or designing and administering preventive interventions.