Diagnostic drivers of psychiatric inpatient bed use in Ireland 2013–2023: implications for service planning

OBJECTIVES: Psychiatric inpatient care is a high-resource component of mental health systems. Understanding the diagnoses driving inpatient care is essential for evidence-based service planning. This study describes psychiatric inpatient bed use in Ireland from 2013 to 2023 by diagnosis, sex, and age group. METHODS: National descriptive analyses using aggregated data from the National Psychiatric Inpatient Reporting System, covering acute inpatient admissions in Ireland. The outcome was total number of inpatient bed days, categorised by ICD-10 diagnostic group. Primary analyses focused on public services, with private services reported separately. We additionally report on child and adolescent mental health services (CAMHS), adult services, and sex-stratified results. RESULTS: Between 2013 and 2023, there were k=3,993,628 public and k=1,879,877 private inpatient bed days. In public services, schizophrenia spectrum disorders accounted for 41.9% of bed days (k=1,673,529), more than twice as many as the next most prevalent diagnosis. Men accounted for 51.2% of acute public bed days. In private adult services, depressive disorders accounted for the largest proportion of bed days (28.5%, k=513,166). In public and private CAMHS, eating disorders accounted for the largest proportion of bed days (25.6%, k=46,850 and 24.4%, k=18,775), respectively. CONCLUSION: This national analysis demonstrates that schizophrenia spectrum disorders represent, by far, the largest diagnostic group, accounting for 42% of public acute psychiatric inpatient beds days, highlighting the sustained, intensive service demands associated with these disorders. These data provide a clear empirical basis for future service planning, highlighting where targeted enhancements to community-based care could most effectively reduce the need for hospitalisation.