Suicidal ideation and suicide risk in Northern Ireland

Authors: Dr Emma Ross, Dr Siobhán Murphy, Dr Aideen Maguire, Dr Denise O’Hagan, Professor Dermot O’Reilly

Date: March 2025

Research summary

This project utilised Northern Ireland's unique National Registry of Self-Harm and Suicidal Ideation to address a critical gap in our understanding about emergency department presentations with suicidal or self-harm ideation and subsequent risk of death. The findings have informed clinical guidance documents and are feeding into policy discussions about suicide prevention strategies, including the All-Party Group on Suicide Prevention.

The research revealed that individuals presenting to emergency departments with suicidal ideation face a tenfold increased risk of subsequent suicide death, with 12% of all suicide deaths having previously presented with ideation. The study is currently informing the development of standardised guidelines for managing suicidal ideation presentations in emergency departments.

This project was conducted by Administrative Data Research Centre Northern Ireland (ADRC NI, part of ADR Northern Ireland) and explored the following research questions:

1. Who is most likely to present to emergency departments with suicidal ideation?
2. What is the risk of suicide and other causes of death following presentation?
3. What factors within people who present with ideation increase mortality risk?

The project involved collaboration with the Public Health Agency and was supported by the Self-Harm Registry Steering Group, creating a strong evidence base for improving the identification of and support for individuals at risk of suicide.

Methods used

The analysis employed a longitudinal approach, examining a cohort of 1.66 million individuals aged 10 and above, registered with a GP in Northern Ireland in April 2012. A key strength of our methodology was access to de-identified individual-level data for the entire population, not just those who presented with ideation. This complete population spine enabled robust comparison of mortality risks between those who presented with ideation (15,267 individuals) and those who did not, providing accurate estimates of the excess risk associated with ideation presentations.

To ensure robust analysis, we utilised several statistical methods. The linked dataset enabled examination of various demographic and socioeconomic factors, including age, sex, deprivation levels, and urban-rural differences. Time-to-event analyses were particularly crucial in identifying critical intervention windows following presentation.

Research findings

Our analysis revealed several significant findings with important implications for public health and clinical practice.

Patterns in the characteristics of people presenting with suicidal ideation

The research identified that 1% of the population (15,267 individuals) presented to emergency departments with suicidal ideation during the study period. Males were 61% more likely to present with ideation, and those under 25 accounted for 38% of people presenting. Urban dwellers and those living alone were twice as likely to present, as were individuals from the most deprived areas.

Risk of death by suicide

By comparing outcomes between people presenting with suicidal ideation and the general population, we identified significantly elevated risk of death among those who presented with ideation. They were ten times more likely to die by suicide, with 12% of all suicide deaths having previously presented with ideation. Beyond suicide risk, the study revealed concerning findings about substance-related mortality, with presenters being 15 times more likely to die from drug-related causes and ten times more likely from alcohol-related causes.

Critical intervention windows

Timing analysis (methods used to examine the timing of events or the impact of time on a given process) identified crucial intervention opportunities. We found that 36% of deaths by suicide occurred within six months of presentation to an emergency department, 50% within 12 months, and 63% within 18 months. Additionally, 40% of individuals were under the influence of alcohol at presentation to an emergency department, with these cases almost four times more likely to die from alcohol-related death.

Research impact

Our research is actively influencing policy and practice development in several key areas:

Policy influence and knowledge translation

Findings have been presented to the All-Party Group on Suicide Prevention in Northern Ireland, which brings together Members of the Legislative Assembly (MLAs) from different political parties to specifically address the issue of suicide prevention. This cross-party group provides a crucial forum for MLAs to work together on suicide prevention initiatives, transcending political boundaries to address this critical public health issue. Members showed particular interest in the identified critical intervention windows and the tenfold increased risk of suicide among ideation presenters. This engagement has sparked important discussions about improving emergency department responses to mental health crises.

The research has already begun influencing clinical practice through its incorporation as supporting evidence in the National Clinical Programme for Self-Harm and Suicide-related Ideation Operational Guidance document. To further support evidence-based policymaking, we are preparing a comprehensive policy brief titled "Self-Harm, Suicidal Ideation & Suicide in Northern Ireland: New evidence from linked administrative data". This document will synthesise our key findings and provide clear, actionable recommendations for policymakers.

NICE Guidelines development

In response to the identified lack of standardised guidelines, we have initiated a Delphi study (a research method used to gather expert opinions and reach consensus on a specific topic) to establish a working group for the development of National Institute for Health and Care Excellence (NICE) guidelines specifically for managing suicidal ideation presentations. This work aims to address the current gap in clinical guidance for managing individuals presenting with suicidal ideation.

Future research translation

Additionally, we are embarking on a new research project that will evaluate specific interventions and assess the impact of mental health assessments on mortality outcomes, including examining the effectiveness of the self-harm intervention programme and analysing the relationship between recommended next care and subsequent outcomes.

Data used

The project analysed data from the following linked datasets:

1. Northern Ireland Registry of Self-Harm and Suicidal Ideation: A national register capturing information on all presentations made to  emergency departments in Northern Ireland with either self-harm or suicidal ideation. This study captured demographic and presentation-specific data on suicidal ideation presentations occurring from 2012-2019, including age at presentation, sex, and time of presentation.
2. National Health Application and Infrastructure Services: A national electronic database containing information on all individuals registered with a General Practitioner (GP) in Northern Ireland. It captures information on date of birth, address, and sex, as well as the Health and Care number – a unique Health and Social Care identifier which enabled linking data across datasets.
3. General Registrar Office Death Records: These provided death records up to December 2019, including date and cause of death.
4. Northern Ireland Neighbourhood Information Service: Supplied area-level information, including deprivation measures and settlement band (urban, intermediate, rural).

All datasets were linked using the Health and Care number as a unique identifier. The linkage and analysis were conducted within the trusted research environment provided by the Honest Broker Service within the Business Services Organisation Northern Ireland.

Research outputs

Publications and reports

• Epidemiology and Psychiatric Sciences, April 2023: Emergency department presentations with suicide and self-harm ideation: a missed opportunity for intervention?
• Supporting evidence in the Irish Health Service Executive’s National Clinical Programme for Self-Harm and Suicide-related Ideation Operational Guidance Document for the Emergency Department Programme
• Policy brief: “Self-Harm, Suicidal Ideation & Suicide in Northern Ireland: New evidence from linked administrative data (in preparation)

Blogs, news reports and videos

• Featured as a resource on the National Suicide Prevention Alliance website.
• ONS Research Excellence Series 2024 recording.

Presentations and awards

• The Lancet UK Public Health Conference 2024: “Risk of suicide following suicidal or self-harm ideation: a population-wide observational cohort study using the Northern Ireland Registry of Self-Harm and Suicidal Ideation.”
• ONS Research Excellence Series 2024: “Emergency Department presentations with suicidal ideation: A missed opportunity for intervention?”
• ADR UK Conference 2023: “Emergency Department presentations with suicidal ideation: A missed opportunity for intervention?”
• Best Oral Presentation, ADR UK Conference 2023
• Shortlisted for two ONS Research Excellence Awards 2024

Acknowledgements

The authors would like to acknowledge the help provided by the staff of the Honest Broker Service (HBS) within the Business Services Organisation Northern Ireland (BSO). The HBS is funded by the BSO and the Department of Health. The authors alone are responsible for the interpretation of the data and any views or opinions presented are solely those of the author and do not necessarily represent those of the BSO.

The authors would also like to acknowledge the support provided by the team at the Northern Ireland Self-Harm Registry and the project steering committee.