Background Little is known about common mental health problems of children and young people (CYP) involved with the family justice system. To address this evidence gap, this study examined records of depression and anxiety in CYP involved in public and private law proceedings using linked, routinely collected, population-level-data across Wales.

Methods Retrospective e-cohort study. We calculated incidence of primary care-recorded diagnoses and symptoms of depression and anxiety of those involved in private and public law proceedings, and in a comparison group, using poisson regression. Depression and anxiety outcomes following court proceedings were evaluated using pairwise cox regression, with age and gender matched controls of CYP who had no involvement with the courts.

Results CYP in the public group had more than twice the risk of depression (adjusted Incidence Rate Ratios (aIRR): 2.2 (95% Confidence Intervals (CI) 1.9–2.6)) and a 20% increased risk of anxiety (aIRR: 1.2 (1.0–1.5)) relative to the comparison group. Those in the private group had 60% higher risk of depression (aIRR: 1.6 (1.4–1.7)) and a 30% increased risk of anxiety (aIRR: 1.3 (1.2–1.4) relative to the comparison group. Following involvement in private law proceedings, CYP were significantly more likely to have depression (Hazard Ratio (HR): 1.9 (1.7–2.1)), and anxiety (HR: 1.4 (1.2–1.5)), than the control group. Those involved in public law proceedings, were more likely to have depression than the control group (HR: 2.1 (1.7–2.6)).

Conclusion Our findings highlight the vulnerability of CYP involved in family court proceedings and increased risk of depression and anxiety. Schools, health professionals, social workers and family support workers have a key role to play in identifying mental health needs and ensuring CYP receive appropriate support both during and after proceedings.