The application belongs to the field of
biochemical detection, and specifically discloses a new use of a GPR18 and other
gene detection
agent combination and a depression detection
reagent. The application of the GPR18 expression level detection agent in the preparation of a
major depressive disorder detection product. The expression amount of GPR18, PDK4, NRG1 and EPHB2 in the application actually has high diagnostic efficiency, and can be used as an independent candidate
diagnostic biomarker. The accuracy of each as a screening indicator reaches 0.6 to 0.8, reaching the standard of a medium-strength screening indicator, and the accuracy of the combined expression amount indicator as a screening indicator reaches 0.779.