Childhood contact with social services is associated with a range of adverse mental health outcomes across the life course, yet there is limited evidence in relation to self-harm and suicidal or self-harm ideation.

Determine the association between all tiers of childhood contact with social services and presentation to an emergency department (ED) with self-harm or thoughts of suicide or self-harm (ideation) in young adulthood.

This retrospective cohort study linked population-wide administrative data on self-harm and ideation presentations recorded in the Northern Ireland Registry of Self-Harm (NIRSH) between 2012 and 2015 to primary care registrations and children’s social care data. Multilevel logistic regression models estimated the association between level of contact with social services in childhood (no contact; referred but assessed as not in need; child in need and child in care) and ED-presenting self-harm or ideation in young adulthood.

There were 253,495 individuals born 1985–1993 with full data, alive and resident in Northern Ireland during 2012–2015 (ages 18–30 years). Of all young adults that presented to EDs with self-harm or ideation, 40.9% had contact with social services in childhood. Young adults with a history of care had 10-fold increased odds of self-harm or ideation (OR = 10.49 [95% CI, 9.45–11.66]) relative to those with no contact. Even those assessed as not in need of any help or support in childhood were three times more likely to present with self-harm or ideation (OR = 3.45 [95% CI, 3.07–3.88]).

Understanding the magnitude of childhood adversity amongst adults that present to EDs with self-harm or ideation may inform clinicians’ understanding and therapeutic decision-making. Whilst EDs provide an important setting in which to administer brief interventions, a multi-agency approach is required to reduce self-harm/ideation in young adults that had contact with social services in childhood.

Children in contact with social services are at high risk for mental ill health, but it is not known what proportion of the child population has contact with social services or how risk varies within this group compared to unexposed peers. We aim to quantify the extent and nature of contact with social services within the child population in Northern Ireland (NI) and the association with mental ill health. We also examine which social care experiences identify those most at risk.

This is a population-based record-linkage study of 497,269 children (aged under 18 years) alive and resident in NI in 2015 using routinely collected health and social care data. Exposure was categorized as (1) no contact, (2) referred but assessed as not in need (NIN), (3) child in need (CIN) and (4) child in care (CIC). Multilevel logistic regression analyses estimated odds ratios (ORs) for mental ill health indicated by receipt of psychotropic medication (antidepressants, anxiolytics, antipsychotics and hypnotics), psychiatric hospital admission and hospital-presenting self-harm or ideation.

Over one in six children (17.2%, n = 85,792) were currently or previously in contact with social services, and almost one child in every 20 (4.8%, n = 23,975) had contact in 2015. Likelihood of any mental ill health outcome increased incrementally with the level of contact with social services relative to unexposed peers: NIN (OR 5.90 [95% confidence interval (CI) 5.10–6.83]), CIN (OR 5.99 [95% CI 5.50–6.53]) and CIC (OR 12.60 [95% CI 10.63–14.95]). All tiers of contact, number of referrals, number of care episodes and placement type were strongly associated with the likelihood of mental ill health.

Children who have contact with social services account for a large and disproportionate amount of mental ill health in the child population. Likelihood of poor mental health across indicators is highest in care experienced children but also extends to the much larger population of children in contact with social services but never in care. Findings suggest a need for targeted mental health screening and enhanced support for all children in contact with social services.