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.
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]