OBJECTIVES: The purpose of this study is to examine the magnitude of and the factors associated with the downward mobility of first-episode psychiatric patients. METHODS: This study used the claims data from the Korean Health Insurance Review and Assessment Service. The study population included 19 293 first-episode psychiatric inpatients diagnosed with alcohol use disorder (International Classification of Diseases, 10th revision [ICD-10] code F10), schizophrenia and related disorders (ICD-10 codes F20-F29), and mood disorders (ICD-10 codes F30-F33) in the first half of 2005. This study included only National Health Insurance beneficiaries in 2005. The dependent variable was the occurrence of downward mobility, which was defined as a health insurance status change from National Health Insurance to Medical Aid. Logistic regression analysis was used to assess factors associated with downward drift of first-episode psychiatric patients. RESULTS: About 10% of the study population who were National Health Insurance beneficiaries in 2005 became Medical Aid recipients in 2007. The logistic regression analysis showed that age, gender, primary diagnosis, type of hospital at first admission, regular use of outpatient clinic, and long-term hospitalization are significant predictors in determining downward drift in newly diagnosed psychiatric patients. CONCLUSIONS: This research showed that the downward mobility of psychiatric patients is affected by long-term hospitalization and medical care utilization. The findings suggest that early intensive intervention might reduce long-term hospitalization and the downward mobility of psychiatric patients.