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

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.