GPT and depressive symptom measurement: Based on the existing "hepato-reno-cerebral axis" hypothesis of multi-organ interaction, this cross-sectional study investigates the associations between routinely measured hepatorenal biomarkers (ALT/AST ratio, BUN and BUN/Cr ratio) and depression risk in geriatric psychiatry inpatients, to validate our hypothesis that these markers are independent risk factors for geriatric depression onset.