A total of 120 patients with MDD who meet the inclusion criteria will be included in the study. Participants will be randomly assigned 1:1:1 to the waiting list group (patients in this group will be treated with selective 5-hydroxytryptamine reuptake inhibitors (SSRIs) only), sham intradermal acupuncture combined with SSRIs (SIA) group and active intradermal acupuncture combined with SSRIs (AIA) group. The study will assess the efficacy and safety of intradermal acupuncture for MDD. In addition, investigator will explore the possible cerebral mechanisms by which IA exerts its antidepressant effects.
