Major depressive disorder (MDD) is a common mental disorder that affects patients' physical health and quality of life. Although traditional acupuncture therapy has certain advantages in improving MDD, there are still some limitations, such as being time-consuming and some people having a fear of acupuncture. Therefore, intradermal needle therapy will be chosen in the treatment of MDD in this study, which is more convenient, shallow needling, and gentle than traditional acupuncture therapy. The study is designed to investigate the therapeutic effect and safety of intradermal needles for MDD.

A total of 120 participants with MDD who meet the inclusion criteria will be included in the study. Participants will be randomly divided into the SSRIs + acupuncture group, acupuncture + placebo group, and SSRIs + sham acupuncture group. This study will evaluate the efficacy and safety of the intradermal needle for MDD and investigate whether the intradermal needle reduces side effects and increases the efficacy of selective serotonin reuptake inhibitors (SSRIs) antidepressants for MDD. Furthermore, the study will demonstrate whether the intradermal needle has a synergistic effect with SSRIs on the treatment of MDD.

Inclusion Criteria:

• 1. Patients should meet the diagnostic criteria of the International Classification of Diseases 10th Edition (ICD-10) diagnostic criteria for depression and are evaluated as moderate or severe MDD according to the severity of depression; 2. 12 ≤ age ≤60, male or female; 3. Participants have clear consciousness and could communicate with others normally; 4. Participants could understand the full study protocol and have high adherence. Written informed consent is signed by themselves or their lineal kin (for minor participants, their guardian should sign the informed consent form for them).

Exclusion Criteria:

• 1. Participants with serious primary diseases of cardiovascular, respiratory, digestive, urinary, hematological, endocrine, neurological disease, and other serious primary diseases, and the disease cannot be effectively controlled clinically; 2. Major depressive disorders caused by organic mental disorders, schizophrenia, bipolar disorder, psychoactive substances, and non-addictive substances; 3. Participants with suicidal tendencies; 4. Pregnant or lactating participants; 5. Participants taking other antidepressants that were not SSRIs or the pharmacological effects of such antidepressants have not been cleared; 6. Participants with intellectual disabilities who cannot cooperate with the questionnaire survey; 7. Participants with bleeding tendency, skin disease, allergic constitution, and allergic to adhesive tape; 8. Participants are participating in other trials.