Method of attempted suicide as predictor of subsequent successful suicide: national long term cohort studyBMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c3222 (Published 13 July 2010) Cite this as: BMJ 2010;341:c3222
- Bo Runeson, professor1,
- Dag Tidemalm, research associate 1,
- Marie Dahlin, senior psychiatrist1,
- Paul Lichtenstein, professor2,
- Niklas Långström, professor23
- 1Department of Clinical Neuroscience, Karolinska Institutet, Division of Psychiatry, St Göran, SE-112 81 Stockholm, Sweden
- 2Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, SE-171 77 Stockholm, Sweden
- 3Centre for Violence Prevention, Karolinska Institutet, Box 23000, SE-104 35 Stockholm, Sweden
- Correspondence to: B Runeson
- Accepted 27 April 2010
Objective To study the association between method of attempted suicide and risk of subsequent successful suicide.
Design Cohort study with follow-up for 21-31 years.
Setting Swedish national register linkage study.
Participants 48 649 individuals admitted to hospital in 1973-82 after attempted suicide.
Main outcome measure 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.
Results 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.
Conclusion 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.
Contributors: BR had the original idea for the study, designed it, analysed results, and drafted the manuscript. DT managed the dataset and performed the statistical analyses. PL and NL were advisers on statistics. DT, NL, PL, and MD interpreted results and co-wrote the paper. BR is guarantor.
Funding: This study was funded by Stockholm County Council and Karolinska Institutet. NL is funded by the Swedish Research Council-Medicine.
Competing interests: All authors have completed the unified competing interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare (1) no financial support for the submitted work from anyone other than their employer; (2) no financial relationships with commercial entities that might have an interest in the submitted work; (3) no spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work; and (4) no non-financial interests that may be relevant to the submitted work.
Ethical approval: This study was approved by the regional ethics committee at Karolinska Institutet (2005/174-31/4). Consent was not obtained but the presented data are anonymised and risk of identification is low.
Data sharing: No additional data available.
- Accepted 27 April 2010
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/2.0/ and http://creativecommons.org/licenses/by-nc/2.0/legalcode.