Background Research consistently suggests that children in care have higher rates of mental ill-health compared to their peers in the community, however, studies exploring the long-term adult mental health outcomes have shown mixed results. The proliferation of research in this area is challenging and to date no comprehensive overview exists. This study synthesised the literature on the mental health outcomes of adults with a history of child welfare involvement.

Methods A systematic scoping review methodology was used to search five electronic databases (MEDLINE, EMBASE, PsychINFO, IBSS, Social Policy and Practice). Two reviewers screened all papers independently. Studies were included if they examined any child welfare exposure (including being known to social services and remaining at home or being removed from the home and placed in foster care or residential care) and adult mental health status.

Results In total 4,591 records were retrieved, of which 53 met the eligibility criteria. Four major themes of child welfare and adult mental health research were identified based broadly on service type: 35 studies examined out-of-home care (OHC) without specifying outcomes by placement type; eleven studies of OHC examined specific placement types; four studies examined both in-home care (IHC) and OHC; and three studies examined IHC services only. Overall, both OHC and IHC were associated with an increased risk of adult mental ill-health, suicide attempt and completed suicide. Potential moderating factors such as gender and care related experiences have been explored but produced conflicting results. Reason for becoming known to child welfare services and experience of abuse or neglect have not been widely explored, nor have outcomes in those who received child welfare services but remained in their own home. Mental health was defined and measured heterogeneously and detail on welfare services received was lacking.

Conclusion This is the first review to systematically map the available evidence on child welfare exposure and adult mental health. There is a need for detailed, longitudinal studies to better understand the aetiology of mental ill health amongst adults with a childhood history of welfare service exposure, with more standardised measures of mental ill-health and more detail from authors on specific care exposure.