Understanding childhood involvement with social services and mental health
: A population-wide data linkage study

  • Sarah McKenna

Student thesis: Doctoral ThesisDoctor of Philosophy


Background: Children known to social services are a vulnerable population in need of help or protection. Mental health is a vital indicator of the wellbeing of children known to social services. However, there are no UK population-level studies concerning the mental health of these children, and their subsequent mental health as adults.

Aim: To examine the mental health of children and adults in Northern Ireland (NI) based on childhood exposure to social services, and to identify the sociodemographic and social care experiences associated with mental ill-health, exploring in particular level of social care exposure, reason for referral or placement in care, age at first referral or placement in care, number of referrals or care episodes, and care placement type.

Methods: A longitudinal, population-wide database of individual-level information on all children known to social services between 1985 and 2015 in NI was created by linking children’s social care, primary care, hospital admission, prescription medication, self-harm and ideation data, and death records. This dataset was used to conduct a series of cross-sectional and longitudinal quantitative analyses to determine the strength of association between level of childhood exposure to social services and mental ill-health in childhood and young adulthood, up to age 36 years. Involvement with social services was classified into four mutually exclusive groups based on highest level: i) no involvement; ii) referred but assessed as not in need (NIN) in every interaction with social services; iii) child in need (CIN); and iv) child in care (CIC). Additional analyses identified which individuals known to social services are most at risk of mental ill-health based on different social care experiences, and explored critical risk periods for mental ill-health during the transition to adulthood.

Results: Likelihood of mental ill-health is elevated for all social care subgroups compared to peers never known to social services, and is highest in care experienced children and adults. Levels of mental ill-health are comparable between those assessed as a child in need, and those deemed not in need of any investigation, surveillance, or services. Children known to social services, and adults previously known, are more likely to receive psychotropic medication, present to an Emergency Department (ED) following an act of self-harm or thoughts of self-harm/suicide, or experience a psychiatric hospital admission compared to peers never known to social services. Children known to social services represent 49.5% of all children in NI that experienced mental ill-health in 2015. Young adults known to social services in childhood represent 40.9% of those who presented to ED with self-harm or ideation, 38.0% of those who experienced a psychiatric admission, and 39.7% of suicide deaths in NI during follow-up.

For young adults known to social services in childhood, the period of transition to adulthood (i.e. in the years immediately after turning 18 years) is one of particular vulnerability to mental ill-health, particularly for care leavers. Likelihood of mental ill-health is higher with proximity to childhood social care involvement and subsequently declines over time, though it remains high in comparison to peers never known to social services. Social care experiences are associated with mental ill-health, and a strong indicator of mental ill-health across life stages is a higher number of referrals to social services in childhood.

Conclusion: This study provides the first UK population-wide evidence that children known to social services at all tiers are a high risk group for mental ill-health, and this increased risk persists into adulthood. Those referred but assessed as not in need are a newly identified at risk group. Findings have already informed policy in NI, and will be useful in targeting resources and interventions to improve mental health.

Thesis embargoed until 31 July 2023.
Date of AwardJul 2022
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsNorthern Ireland Department for the Economy
SupervisorAideen Maguire (Supervisor), Dermot O'Reilly (Supervisor) & Michael Donnelly (Supervisor)


  • Social services
  • looked after children
  • children in need
  • care experienced
  • mental health
  • psychotropic medication
  • self-harm
  • suicidal ideation
  • suicide
  • psychiatric admission

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