BACKGROUND: Most mental health difficulties (MHD) emerge during adolescence and early adulthood, placing young people at an increased risk for co-occurring physical and sexual health challenges. Shared models of care (SMOC) to connect specialist mental health care with physical and/or sexual health have been developed to address these health needs among young people with MHD. We aimed to identify and characterise SMOC that integrate physical and/or sexual healthcare for young people with MHD, and to synthesise SMOC implementation determinants using the Consolidated Framework for Implementation Research (CFIR) for policy makers, commissioners and practitioners seeking to strengthen youth-integrated service delivery.

METHODS: Five electronic databases and key grey literature sites were searched in October 2024. Studies were eligible for inclusion if they predominantly included young people (aged 10–25) with an MHD. SMOC had to address MHD as a primary concern or have parity with the physical and/or sexual health concern(s) being addressed. Key study details were extracted and were appraised using the mixed methods appraisal tool. Screening was conducted in duplicate, with extraction and appraisals conducted by one team member and verified by a second. Findings were thematically synthesised and mapped to CFIR domains to inform implementation planning in youth health systems.
[Note: Studies focusing on youth without MHD, those solely with substance use disorders, or adults aged ≥ 26 were excluded.]

RESULTS: Search results identified 25 relevant SMOC to include in the review. Almost all models (n = 23/25) addressed shared care between mental and physical health, while nine addressed mental and sexual health and seven addressed mental, physical and sexual health needs. Reporting quality varied but most SMOC included referral pathways, assessment, treatment and external support components. Barriers frequently mapped to the inner and outer setting CFIR domains, with high staff turnover (n = 9) and societal stigma towards mental health (n = 7) common concerns. Enablers frequently mapped to the process and innovation constructs, including offering youth-specific care models (n = 7) and clear communication between services (n = 5).

CONCLUSIONS: Despite evidence supporting the need for an integrated care approach, implementation remains limited by setting-specific barriers. Findings highlight the need for service planning and developing tailored, youth-specific models to ensure a holistic approach to care is available to young people experiencing MHD.