Models of Care for Mental Health Nurse Practitioners in Emergency Department Settings: A Scoping Review Across High-Income Countries.

This scoping review examined and synthesised existing literature on models of care involving Mental Health Nurse Practitioners (MHNPs) practising or consulting within Emergency Department (ED)-based Emergency Mental Health (EMH) services. EDs are a key access point for mental health care and often provide first contact or after-hours support for people experiencing crisis, reinforcing their central role within the mental health system. The review highlights the need for timely, safe and specialised mental health care within EDs to strengthen the quality, safety and responsiveness of EMH services. Given the limited ED-specific MHNP literature, studies involving related advanced mental health nursing roles were also included where functions overlapped with MHNP practice, although these roles were not considered equivalent. Using Arksey and O'Malley's framework, 13 ED-specific studies were included: two quantitative, two qualitative, five mixed-methods, three realist or realist-informed evaluations and one descriptive or pilot service evaluation. Three themes were identified: consumer outcomes and timely access to care; MHNP roles within ED service models; and stakeholder perspectives and systemic challenges. Across studies, MHNPs and related advanced mental health nursing roles were associated with improved access to specialist assessment, enhanced care coordination, reduced psychological distress and high consumer and staff satisfaction. However, evidence was largely derived from early-stage, single-site evaluations. Barriers relating to role visibility and organisational support also limited sustainability. Overall, MHNP roles remain under-researched, highlighting the need to identify system-level enablers supporting effective integration and impact.