Methods of non-fatal self-harm may help to predict future risk of suicide

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NICE guidance recommends that all people who self-harm and are admitted to hospital are given mental health and risk assessment:

Everyone who has self-harmed should have a comprehensive assessment of needs and risk; engaging the service user is a prerequisite.
– Taken from NICE Self-harm guidance (CG16), Nov 2004

This new prospective cohort study conducted by a research team from Oxford University’s Centre for Suicide Research, set out to investigate weather the most recent method of non-fatal self-harm could be used to predict the risk of future suicide.

The researchers took data from the Multicentre Study of Self-harm conducted in 3 centres in England from 2000-2010. Over 30,000 people presented to emergency departments in 6 hospitals from 2000-2007 with non-fatal self-harm. 41.3% of this cohort were male and the median age was 27 years old.

The outcome of interest was suicide and this was measured over a 3-11 year follow-up period.

Here’s what they found:

  • 378 individuals (1.25% of the total cohort) killed themselves during the study
  • 76.2% of participants had one episode of self-harm during the study, 13.3% had two episodes, 10.7% had three or more episodes
  • When compared with self-poisoning, all other methods of self-harm at the last episode were associated with a significantly increased risk of suicide as a whole:
    • Cutting (HR 1.79, 95% CI 1.62 to 1.98)
    • Hanging/asphyxiation (HR 2.65, 95% CI 2.36 to 2.97)
    • Carbon monoxide (CO)/other gas (HR 5.02, 95% CI 2.33 to 10.86)
    • Traffic related (HR 4.41, 95% CI 2.93 to 6.63)
    • All other self-injuries (HR 1.88, 95% CI 1.01 to 3.50)
  • When compared with self-poisoning, most other methods of self-injury at the last episode were associated with a significantly increased risk of suicide by self-injury (defined as all methods other than poisoning):
    • Cutting (HR 2.29, 95% CI 1.67 to 3.13)
    • Hanging/asphyxiation (HR 4.15, 95% CI 3.11 to 5.54)
    • CO/other gas (HR 6.70, 95% CI 1.70 to 26.49)
    • Traffic related (HR 5.65, 95% CI 2.40 to 13.32)
  • Other methods of self-injury were not significantly associated with risk of suicide by self-injury (HR 2.55, 95% CI 0.93 to 6.99)
  • People presenting with all methods of self-harm had similar risks of subsequent suicide by self-poisoning
  • 32% of people who killed themselves used the same method for their death as for their last episode of self-harm

It is important to stress that this study focused specifically on people who were admitted to an emergency department for self-harm and so does not include others who never reach hospital.

The authors concluded:

Method of self-harm may aid identification of individuals at high risk of suicide. Individuals using more dangerous methods (e.g. hanging, CO/other gas) should receive intensive follow-up. Method changes in repeated self-harm were not associated with suicide. Our findings reinforce national guidance that all patients presenting with self-harm, regardless of method, should receive a psychosocial assessment.

If you need help

If you need help and support now and you live in the UK or the Republic of Ireland, please call the Samaritans on 116 123.

If you live elsewhere, we recommend finding a local Crisis Centre on the IASP website.

We also highly recommend that you visit the Connecting with People: Staying Safe resource.

Links

Bergen H, Hawton K, Waters K, Ness J, Cooper J, Steeg S, Kapur N. How do methods of non-fatal self-harm relate to eventual suicide? J Affect Disord. 2012 Feb;136(3):526-33. Epub 2011 Nov 29. [PubMed abstract]

Self-harm: The short-term physical and psychological management and secondary prevention of self-harm in primary and secondary care (PDF). NICE CG16, Nov 2004.

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