Association between mental health social worker staffing in psychiatric emergency wards and readmission outcomes: A nationwide survey in Japan

The mental healthcare system in Japan is transitioning from institution‐based to community‐based treatment. To prevent prolonged hospitalization and community integration of psychiatric patients, mental health social workers (MHSWs) are pivotal in coordinating post‐discharge arrangements for psychiatric inpatients. This study aimed to propose a care model to improve clinical outcomes in psychiatric emergency wards in Japan.We conducted a mail‐in questionnaire survey targeting medical facilities with psychiatric emergency wards. We collected data of the psychiatric care system, including facility profiles, staffing conditions and caseloads, and the provided psychiatric services and treatment options. Using multiple regression analyses, we explored associations between these data and clinical outcomes, focusing on the average number of days for hospitalization and the integration of patients into a community.Data were collected from 82 facilities (response rate, 45.8%). The average number of days for hospitalization and community integration were 64.7 and 327.9 days, respectively. The caseloads for MHSWs were significantly associated with longer hospitalization (β = 0.31, p = 0.009) and shorter duration of community living (β = −0.28, p = 0.027).The clinical performance in psychiatric emergency wards surpassed the Japanese government's targets regarding these outcomes. We found that heavy caseloads on MHSWs were associated with worse clinical outcomes for patients in psychiatric emergency wards. These findings suggest that reducing MHSW caseloads (≤20 cases) may be a potential interventional strategy to prevent prolonged hospitalization and promote successful community integration of patients.