Health service use for young males and females with a mental disorder is higher than their peers in a population-level matched cohort

BACKGROUND: To inform healthcare planning and resourcing, population-level information is required on the use of health services among young people with a mental disorder. This study aims to identify the health service use associated with mental disorders among young people using a population-level matched cohort. METHOD: A population-based matched case-comparison retrospective cohort study of young people aged ≤ 18 years hospitalised for a mental disorder during 2005–2018 in New South Wales, Australia was conducted using linked birth, health, and mortality records. The comparison cohort was matched on age, sex and residential postcode. Adjusted rate ratios (ARR) were calculated for key demographics and mental disorder type by sex. RESULTS: Emergency department visits, hospital admissions and ambulatory mental health service contacts were all higher for males and females with a mental disorder than matched peers. Further hospitalisation risk was over 10-fold higher for males with psychotic (ARR 13.69; 95%CI 8.95–20.94) and anxiety (ARR 11.44; 95%CI 8.70-15.04) disorders, and for both males and females with cognitive and behavioural delays (ARR 10.79; 95%CI 9.30-12.53 and ARR 14.62; 95%CI 11.20-19.08, respectively), intellectual disability (ARR 10.47; 95%CI 8.04–13.64 and ARR 11.35; 95%CI 7.83–16.45, respectively), and mood disorders (ARR 10.23; 95%CI 8.17–12.80 and ARR 10.12; 95%CI 8.58–11.93, respectively) compared to peers. CONCLUSION: The high healthcare utilisation of young people with mental disorder supports the need for the development of community and hospital-based services that both prevent unnecessary hospital admissions in childhood and adolescence that can potentially reduce the burden and loss arising from mental disorders in adult life. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12913-022-08789-3.