An Irish study by Griffin et al.1 assessed suicide risk following hospital attendance with self-harm. This is an important Irish study as it calculated the risk of suicide among those with a history of hospital-presenting self-harm using national-level data.

Background

Self-harm can be defined as intentional self-injury or poisoning, irrespective of motive.1 There are many ways people can intentionally harm themselves, including poisoning with tablets or toxic chemicals, misusing alcohol or drugs, or cutting or burning their skin.

History of self-harm is the strongest predictor of suicide. It is estimated that the risk of suicide is up to 100 times higher in those that attempted self-harm within the last year.2 Within 10 years, it is estimated that between 5% and 10% of adults who have self-harmed will have died by suicide. Several studies and a systematic review have reported that the 1-year of risk of suicide after previous self-harm episodes is between 0.5% and 2.0%.3,4,5

Several different factors have been shown to play a role in the risk profile among those who presented to hospital with self-harm, including age, sex, and violent self-harm. Though the findings have shown that the highest suicide risk is among men, the highest relative risk was among women.1,2 This means that women with a history of self-harm were more likely to die by suicide than women with no history of self-harm, whereas men overall had a higher risk of suicide. A violent self-harm method (such as hanging and other self-injury methods) was also found to be the strongest examined risk factor of suicide in those aged 20 years or older.2

Suicide prevention strategies and interventions can benefit from a greater understanding of suicide risk after self-harm and thereby offer a more tailored approach in mitigating factors that can influence suicide risk.

Methods

The study used data from National Self-Harm Registry Ireland (NSHRI) from the period 1 January 2015 to 31 December 2017. The NSHRI is one of the only dedicated national self-harm registries worldwide, and it records all self-harm presentations to emergency departments in Ireland. The main aim of the study was to examine suicide risk among those who presented to emergency departments in Ireland. The study also sought to identify subgroups that were at an elevated risk of suicide using individual characteristics such as age, sex, self-harm method, and previous history of self-harm. Data collected during this period were also validated using the Irish Probable Suicide Deaths Study (IPSDS). The IPSDS collects national coronial data on probable suicides.

Results

In total, 23,764 individuals attended emergency services after self-harm during the study period. Over one-half (54.4%) of these were female. More than one-third (37.3%) of these presentations were in individuals aged under 25 years. Poisoning or drug overdose only was the most common method (59.5%) of self-harm in those that presented to emergency services. Additionally, 17.6% of individuals presented with self-cutting only. A combination of methods, including drug overdose and self-cutting, or drug overdose and hanging, were used by a minority of individuals. Nearly one-third (31.4%) of individuals had consumed alcohol as part of the self-harm episode. A minority of individuals (17.1%, n=4066) had a history of presentation to hospital having self-harmed in the 12-months preceding their most recent presentation.

The study found that the 1-year risk of suicide in this cohort was 0.9%, with a total of 217 individuals dying by suicide during the study follow-up. The 12-month cumulative incidence of suicide for male, female, and all persons was 1.3%, 0.6%, and 0.9%, respectively. Overall, the 12-month risk of suicide was more than 80 times higher in the hospital-presenting self-harm cohort relative to the general population. Nearly 38.7% of these suicides occurred within the first month following a self-harm episode. Factors such as increasing age, male sex, prior self-harm history, and previous hanging as a method of self-harm were all linked to an elevated suicide risk.

Discussion

Overall, nearly 24,000 individuals presented to emergency services with self-harm during the 2-year study period. In total, 217 individuals died by suicide during the follow-up period. The 1-year risk of suicide was 0.9% for this cohort. These findings are in line with previously reported international figures.

The study highlights the critical need for safety planning and timely follow-up after hospital-presenting self-harm episodes. Suitable interventions are also needed during the first month after the period of self-harm, where the risk of suicide is greatest. Timely and targeted interventions are needed particularly among the youngest and oldest age categories.

Conclusion

The risk of suicide is elevated after the period of self-harm. Several factors associated with an elevated suicide risk have been identified, including male sex, older age, and hanging as a self-harm method. However, prediction of suicide risk remains very difficult, and all patients should receive appropriate after-care to reduce mortality.

1    Griffin E, Corcoran P, Arensman E, et al. (2023) Suicide risk following hospital attendance with self-harm: a national cohort study in Ireland. Nat Mental Health, 1: 982–989. Available from: https://www.drugsandalcohol.ie/39829/

2    Tidemalm D, Beckman K, Dahlin M, et al. (2015) Age-specific suicide mortality following non-fatal self-harm: national cohort study in Sweden. Psychol Med, 45(8): 1699–1707.

3    Gibb SJ, Beautrais AL and Fergusson DM (2005) Mortality and further suicidal behaviour after an index suicide attempt: a 10-year study. Aust NZ J Psychiatry, 39(1–2): 95–100.

4    Owens D, Horrocks J and House A (2002) Fatal and non-fatal repetition of self-harm. Systematic review. Br J Psychiatry, 181: 193–199.

5    Carroll R, Metcalfe C and Gunnell D (2014) Hospital presenting self-harm and risk of fatal and non-fatal repetition: systematic review and meta-analysis. PLoS One, 9(2): e89944.