Open Access

ARTICLE

Factors Influencing Length of Stay and Symptom Improvement among Psychiatric Patients by Diagnosis: Analysis of the Korea National Survey

Soo-Hyun Sung¹, Seungwon Shin², Seok-Hwan Kim³, Minjung Park^4,*

1 School of Korean Medicine, Wonkwang University, Iksan, Republic of Korea
2 College of Korean Medicine, Sangji University, Wonju, Republic of Korea
3 Department of Health and Medical Informatics, WISE Campus, Dongguk University, Gyungu, Republic of Korea
4 Department of Preventive Medicine, College of Korean Medicine, Gachon University, Seungnam, Republic of Korea

* Corresponding Author: Minjung Park. Email:

(This article belongs to the Special Issue: Evidence-based Approaches to Managing Stress, Depression, Anxiety, and Suicide)

International Journal of Mental Health Promotion 2026, 28(4), 13 https://doi.org/10.32604/ijmhp.2026.077710

Received 15 December 2025; Accepted 17 March 2026; Issue published 28 April 2026

Abstract

Objectives: Psychiatric inpatient care plays a critical role in stabilizing acute mental health crises, yet the optimal length of stay (LOS) and its impact on short-term clinical outcomes remain poorly defined across diagnostic groups. This study aimed to examine how LOS in psychiatric inpatient units is associated with clinical improvement at discharge and to determine whether this association differs across major diagnostic groups, using nationally representative hospital discharge data from Korea. Methods: A cross-sectional secondary analysis was conducted using the 2022–2023 Korea National Hospital Discharge In-depth Injury Survey. Adults whose primary discharge diagnosis was a mental or behavioral disorder (Korean Standard Classification of Diseases, F00–F99) were included (n = 3700). Sociodemographic characteristics, hospital factors, comorbidities (Charlson Comorbidity Index), psychiatric subdiagnoses, surgical procedures, and LOS were analyzed. Results: The average LOS was longer in the improvement group (21.48 days) compared to the non-improvement group (12.18 days) (p < 0.001). Longer LOS was associated with higher odds of improvement overall (OR = 1.04, 95% CI: 1.03, 1.04; p < 0.001) and showed strong diagnosis-specific effects: schizophrenia (OR = 5.27, 95% CI: 3.41, 8.09), dementia (OR = 2.38, 95% CI: 0.10, 40.9), alcohol use disorder (OR = 2.21, 95% CI: 0.79, 6.36; interaction OR = 2.11, p < 0.05), whereas non-significant or weaker in mood disorders and substance use disorders (OR = 0.60, 95% CI: 0.17, 2.13) Significant interaction effects indicated that the magnitude and shape of the LOS outcome relationship differed by diagnostic category. Conclusions: Longer length of stay was significantly associated with clinical improvement at discharge, with the strongest effects observed in schizophrenia, dementia, and alcohol use disorder, but limited benefit in substance use disorders. These diagnosis-specific patterns support tailored inpatient duration policies rather than uniform psychiatric bed-day targets.

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