This project plans to recruit 60 patients with depression, randomly assigning them to either the CAVO group or the bergamot essential oil group, with 30 participants in each. Quantitative measurement will be conducted using fNIRS technology to assess the impact of the intranasal CAVO pathway on brain functional connectivity during rest and brain activation during task performance. The antidepressant effects of CAVO will be evaluated using standardized depression scales, and target brain regions for CAVO's action will be identified through this process.