Brain injuries linked with potential risk of suicide, new study finds

Adults who experience a head injury face a substantially higher risk of attempting suicide compared to those without such injuries, according to the findings from a new UK-based study.

Published in Neurology®, the medical journal of the American Academy of Neurology, the study was led by University of Birmingham researchers. The paper is the first of its kind to examine suicide risk across all types of head injuries in a general population, moving beyond the traditional focus on traumatic brain injuries (TBIs) in military, athletic or hospital settings.

The population-based matched cohort study used nationally represented electronic primary healthcare records from more than 1.8 million adults, linked with Hospital Episode Statistics and Office for National Statistics data.

Researchers found that people with head injuries were 21% more likely to attempt suicide than those without, after analysing data across a 20-year period.

Key Findings:

• Researchers found that people with head injuries were 21% more likely to attempt suicide than those without, even after adjusting for age, sex, deprivation, and mental health history.
• The incidence rate was 2.4 per 1,000 person-years in individuals with head injuries, compared to 1.6 per 1,000 person-years in the control group. This translates to an absolute increase in risk of 0.7% (1.3% vs 0.6%), yet the adjusted hazard ratio reported was 21%, and
• Elevated risk was observed across all subgroups, including individuals with no prior mental health conditions, highlighting that head injuries alone are linked to increased psychological vulnerability.

Professor Nicola Adderley, Professor of Epidemiology and Real-World Evidence at the University of Birmingham and a lead author of the study, said: “Our findings show that the impact of head injuries are not limited to just physical symptoms or repercussions. They can have profound psychological consequences. Suicide risk assessments should be considered for anyone with a recent head injury, regardless of their mental health crhistory, to improve and safeguard patient outcomes.”

Critical window for intervention

In the UK alone, nearly 6,000 deaths each year are attributed to suicide whilst the number of attempts is significantly higher. The study’s findings showed that the risk of suicide attempt was highest in the first 12 months following a head injury, suggesting a critical window for intervention.

While the risk declined over time, it remained elevated compared to those without head injuries. Researchers also found that social deprivation and a history of mental health conditions further amplified the risk.

While suicide attempts were more common among those with head injuries, the study did not find a significant increase in deaths by suicide after accounting for competing risks such as other causes of death; suggesting that head injuries may lead to more frequent non-fatal attempts.

Researchers are calling for the following changes in healthcare settings:

• Routine suicide risk screening in primary and secondary care settings for patients with head injuries.
  
  
• Enhanced mental health support, particularly during the first 12 months post-injury; with public awareness campaigns to help families and caregivers recognise warning signs.
  
  
• The development and testing of suicide risk assessment and prevention strategies for people with head injuries should be investigated, especially within the first 12 months post-head injury and irrespective of mental health history.

Professor G. Neil Thomas, Professor of Epidemiology and Research Methods and a lead author of the study, said: “These findings have implications for both clinical practice and health policy; highlighting the urgent need for targeted mental health and wellbeing support.

“The development and testing of robust suicide risk assessment and prevention strategies for people with head injuries should be further investigated; especially within the first 12 months post-head injury and irrespective of mental health history.”

The research utilised data from the Clinical Practice Research Datalink (CPRD), linked with hospital and mortality records, covering a 20-year period (2000–2020). Ethical approval was granted by the Health Research Authority and CPRD Independent Scientific Advisory Committee.