Method of attempted suicide as predictor of subsequent successful suicide: national long term cohort study

TLDR

The study examined whether the method of an initial suicide attempt predicts the risk of later completed suicide in a Swedish cohort of 48,649 patients followed for 21–31 years. Cox regression models compared each attempt method to poisoning as reference, yielding hazard ratios; 5,740 (12 %) participants died by suicide during follow‑up. Hanging, strangulation, or suffocation attempts conferred the highest risk (HR ≈ 6.2), with 87 % of those who later died doing so within a year, whereas other methods had lower but still elevated risks (HR 1.8–4.0), and most decedents used the same method as their first attempt, indicating that method choice predicts future suicide and warrants intensified aftercare for high‑risk methods.

Abstract

To study the association between method of attempted suicide and risk of subsequent successful suicide.Cohort study with follow-up for 21-31 years.Swedish national register linkage study.48,649 individuals admitted to hospital in 1973-82 after attempted suicide.Completed suicide, 1973-2003. Multiple Cox regression modelling was conducted for each method at the index (first) attempt, with poisoning as the reference category. Relative risks were expressed as hazard ratios with 95% confidence intervals.5740 individuals (12%) committed suicide during follow-up. The risk of successful suicide varied substantially according to the method used at the index attempt. Individuals who had attempted suicide by hanging, strangulation, or suffocation had the worst prognosis. In this group, 258 (54%) men and 125 (57%) women later successfully committed suicide (hazard ratio 6.2, 95% confidence interval 5.5 to 6.9, after adjustment for age, sex, education, immigrant status, and co-occurring psychiatric morbidity), and 333 (87%) did so with a year after the index attempt. For other methods (gassing, jumping from a height, using a firearm or explosive, or drowning), risks were significantly lower than for hanging but still raised at 1.8 to 4.0. Cutting, other methods, and late effect of suicide attempt or other self inflicted harm conferred risks at levels similar to that for the reference category of poisoning (used by 84%). Most of those who successfully committed suicide used the same method as they did at the index attempt-for example, >90% for hanging in men and women.The method used at an unsuccessful suicide attempt predicts later completed suicide, after adjustment for sociodemographic confounding and psychiatric disorder. Intensified aftercare is warranted after suicide attempts involving hanging, drowning, firearms or explosives, jumping from a height, or gassing.