A randomized controlled trial was conducted to observe the improvement of mild to moderate depressive symptoms in children and adolescents with the aromatic herbal compound Cang Ai Volatile Oil (CAVO) and to evaluate the effectiveness and safety of the clinical application of CAVO.

The trial was divided into: screening period, pre-treatment period, treatment period (first session, second session) and follow-up period.

(1) Screening period (14 days before intervention to 2 days before intervention): 108 patients with mild to moderate adolescent depression, regardless of gender, are to be enrolled. Patients will sign an informed consent form and will complete the screening period from the 14th pre-intervention day to the 2nd pre-intervention day.

(2) Pre-treatment (1 day prior to intervention): Patients who meet all inclusion criteria and do not meet any of the exclusion criteria will obtain a randomisation number 1 day prior to dosing and will be randomised in a 1:1:1 ratio to either the trial group (Group A), positive drug group (Group B) or blank control group (Group C). Subjects undergo an alcohol breath test and urine drug screen on an empty stomach at the test site to determine if they meet the entry criteria. Blood tests will be taken on an empty stomach on the day of the trial for testing, followed by food and 30 minutes later, blood pressure and EEG measurements will be taken and a depression scale will be completed after completion of NIR brain function measurements.

(3) Treatment period (first course: weeks 1 to 4, second course: weeks 5 to 8).

1. Test group: Each subject was given a sufficient amount of CAVO aromatherapy patch + fluoxetine hydrochloride mimetic at a concentration of 3%. The subject was instructed to fix the aromatherapy patch on the near-nasal part of the mouthpiece daily and complete two sniffing inhalations at fixed times (07:45-08:00 and 19:45-20:00) daily during the course of the treatment period, each time for 15 minutes, and to take 1 tablet of fluoxetine mimetic orally once a day. times.

2. Positive drug group: Each subject was given a sufficient amount of CAVO aromatherapy patch + fluoxetine hydrochloride tablet (20mg/tablet) at a concentration of 0.1%, and was instructed to take fluoxetine hydrochloride tablet (20mg/tablet) orally (10mg/dose, once a day). The aromatherapy patch was applied to the nasal area of the mask once a day.

3. Blank control group: Subjects were given a sufficient amount of CAVO aromatherapy patch + fluoxetine hydrochloride mimetic (20mg/tablet) at a concentration of 0.1% and were instructed to fix the aromatherapy patch on the near nasal area of the mouthpiece twice a day during the treatment period at fixed times (07:45-08:00 and 19:45-20:00) and to take 1 tablet of fluoxetine mimetic by mouth for 15 minutes each time. tablet of fluoxetine mimetic (20mg/tablet), 10mg/dose, once a day.

   Subjects will be required to complete blood pressure measurements, EEG measurements and NIR brain function measurements at the end of the first and second sessions respectively and then complete a depression rating scale. Blood will also need to be taken on an empty stomach at the end of the treatment period for submission for testing.

4. Follow-up period: (Week 9 to 10) Patients complete a follow-up examination at week 9 to 10 after the first dose. The investigator will continue to follow up with you by telephone for 1 week (at least 2 times, 1 day and 1 week after the end of the trial) to see how you are doing. You will be asked to answer a call back from your doctor and you will need to cooperate with the investigator's questioning.

Inclusion Criteria:

• Meets the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and International Classification of Diseases (ICD) 10th Revision diagnostic criteria for mild to moderate depressive episodes, either first or recurrent, and not accompanied by psychotic symptoms.
• Meeting the diagnostic criteria for depression in Chinese medicine.
• 10 to 18 years of age (including borderline values), either sex.
• Depression scale: BDI-2, HAMD depression scale score of mild to moderate
• Healthy sense of smell, no allergic diseases or respiratory diseases.
• Have not used antidepressants and other psychiatric drugs or physiotherapy such as electroconvulsive or transcranial magnetic stimulation for at least 1 week prior to the examination.
• Depressive episodes lasting 2 weeks or more.
• All subjects have volunteered to participate and signed an informed consent form, as approved by the hospital's ethics committee.

Exclusion Criteria:

• A history of alcohol and drug dependence is strictly excluded.
• Current or prior diagnosis of a major psychiatric disorder other than depression consistent with DSM-5, such as bipolar disorder, neurodevelopmental disorder, neurocognitive disorder, schizophrenia, psychotic disorder, obsessive-compulsive disorder, panic disorder, post-traumatic stress disorder, antisocial personality disorder, etc.
• Depression with a history of organic brain disease and endocrine disorders or secondary to other psychiatric disorders.
• Persons at high risk of suicide: e.g., suicide attempts, recent suicide attempts, and those without family supervision
• Those with a history of manic or hypomanic episodes.
• Regularly taking antidepressants within 2 weeks prior to screening and not having discontinued psychotropic medication for 7 half-lives (at least 2 weeks for monoamine oxidase inhibitors and at least 1 month for fluoxetine) prior to randomisation to the group.
• Patients who have received physical therapy such as MECT, TMS, Vagus Nerve Stimulation (VNS), Deep Brain Stimulation (DBS), and other treatments such as light therapy, music therapy, exercise therapy, and acupuncture in the 3 months prior to screening.
• Patients with severe or unstable cardiovascular, respiratory, hepatic, renal, endocrine, haematological or other systemic disease which, in the opinion of the investigator, makes them unsuitable for enrollment in this study.
• Persons with known hypersensitivity to the test drug, or who are allergic.
• Those who have used the clinical trial drug within 3 months prior to the first dose, or those who plan to participate in other clinical trials during this study (ask, enquire).

References to deidentified individual participant data (IPD) sets and supporting information.