Inclusion Criteria:
1. Age range from 18 to 65 years old (including boundary values), both male and female;
2. Single or recurrent episodes that meet the diagnostic criteria for depression in DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition);For patients with a single episode, the duration of this depressive episode must be ≥90 days.
3. Screening and baseline periods, the total score of the Montgomery Asperger Depression Rating Scale (MADRS) was ≥ 26 points;
4. Screening and baseline periods, with a Clinical Global Impression Scale Disease Severity (CGI-S) score of ≥ 4 points;
5. Voluntary participation in clinical trials, able to sign informed consent forms, and able to understand and comply with research procedures.
Exclusion Criteria:
1. Individuals with a history of severe drug allergies or allergies to Piper Piper (pepper plant) ;
2. Those who have used at least two antidepressants in sufficient dosage and duration (treated according to the maximum dosage in the instructions for at least 4 weeks) in a single or current episode in the past but still have no effect;
3. The patients of depression secondary to other mental or physical illnesses;
4. Patients of depression with accompanying psychiatric symptoms;
5. Significant suicidal attempt or behavior within the past year, with a score of ≥ 3 on the 10th item (suicidal ideation) of the MADRS scale;
6. Individuals with a history of epileptic seizures (excluding convulsions caused by febrile seizures in children);
7. Individuals who have received depression related systemic physical therapy within 3 months prior to their first administration: modified electroconvulsive therapy (MECT), transcranial magnetic stimulation (TMS), vagus nerve stimulation (VNS), deep brain stimulation (DBS), phototherapy, or systemic psychotherapy;
8. Systematically receiving antidepressant treatment within the first 2 weeks of randomization, or discontinuing antidepressant medication for less than 5 half-lives before randomization;
9. Those with severe unstable cardiovascular and cerebrovascular diseases, respiratory system diseases, gastrointestinal diseases, liver diseases, kidney diseases, blood diseases, endocrine diseases, or a history of such physical diseases;
10. Accompanied by a history of malignant tumors (excluding cured skin basal cell carcinoma and cervical carcinoma in situ);
11. Screening or baseline electrocardiogram abnormalities that have clinical significance and are deemed unsuitable for inclusion by investigators, such as male QTcF ≥ 450 ms, female QTcF ≥ 470 ms, or having a history of long QT syndrome;
12. During the baseline period, those with a reduction rate of ≥ 25% in the MADRS scale score compared to the screening period;
13. A history of symptomatic orthostatic hypotension (i.e. orthostatic syncope) with clinical significance;
14. During the screening or baseline period, TBIL is above 2 times the upper limit of normal value, and ALT or AST is above 2 times the upper limit of normal value; Cr is higher than 1.2 times the upper limit of normal value;
15. Thyroid dysfunction (TSH above 1.2 times the upper limit of normal value or below 0.8 times the lower limit of normal value) or the presence of hyperthyroidism or hypothyroidism determined by the investigators; Individuals with a history of elevated intraocular pressure or narrow angle glaucoma;
16. Screening period, drug abuse screening positive individuals;
17. A history of alcohol dependence within one year prior to screening(Drinking alcohol for more than 5 years, equivalent ethanol intake, daily alcohol consumption: men \>40 g/d, women \>20 g/d; drinking ≤5 years, equivalent ethanol intake, history of heavy drinking (\>80 g/d) within 2 weeks);
18. Pregnant and lactating women, male or female subjects who have a family planning or are unable to take effective contraceptive measures within 30 days after signing the informed consent form and ending the trial;
19. Screening for individuals who have participated in clinical trials and taken investigational drugs within the first 30 days;
20. The investigators believe that the subjects have poor compliance or there are other clinical, social, or family factors that are not suitable for enrollment.
