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

• Published in: Psychological medicine 2015-06, Vol.45 (8), p.1699-1707
• Main Authors: Tidemalm, D., Beckman, K., Dahlin, M., Vaez, M., Lichtenstein, P., Långström, N., Runeson, B.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age Distribution; Child; Cohort Studies; Female; Follow-Up Studies; Humans; Incidence; Male; Medicin och hälsovetenskap; Mortality; Original Articles; Risk Assessment; Risk Factors; Self destructive behavior; Self-Injurious Behavior - epidemiology; Sex Distribution; Studies; Suicide - statistics & numerical data; Suicides & suicide attempts; Sweden - epidemiology; Young Adult
• ISSN: 0033-2917; 1469-8978; 1469-8978
• DOI: 10.1017/S0033291714002827

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. 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. 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. 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.