Part 1: This study will include 30 patients with MDD (MDD group) and 30 HC participants (HC group). PTG and IRT, respectively, will be adopted to assess 2 kinds of biological specificity of MDD-related acupoints: pain sensitivity specificity and thermal specificity. Based on the results of the PTG and IRT tests, the potentially superior acupoints for the treatment of MDD will be selected separately. After statistical analysis of the data from PTG and IRT tests, 4 pressure pain threshold strong response acupoints (PSA) and 4 temperature strong response acupoints (TSA) will be selected, respectively.~Part 2: A total of 120 participants with MDD who meet the inclusion criteria will be included in the study. Patients with MDD who met the criteria will be randomly divided 1:1:1:1 into 4 groups: waiting treatment (WT) group, clinical common acupoint (CCA) group, TSA group, and PSA group. All participants received basic therapeutic medication for the use of one or more antidepressants. Dosing and dosage will be adjusted by a specialist. The Patient Health Questionnare-9 (PHQ-9) and the MOS item short form health survey (SF-36) will be used as clinical efficacy outcome indicators, and each group's incidence of adverse effects will be observed. This study will investigate the effectiveness and safety of IA based on changes in the biological specificity of acupoints for MDD.
Acupoints are the stimulus points and reactive points for acupuncture to treat diseases. Therefore, this study is designed to detect the pain threshold and temperature of biological specificities of acupoints in healthy control (HC) participants and major depressive disorder (MDD) participants by using pressure pain threshold gauge (PTG) and infrared thermography (IRT). Based on the results of the PTG and IRT tests, the potentially superior acupoints for the treatment of MDD will be selected separately. Then, different acupoint groups selected based on different biological specificities tests will be used for clinical treatment to evaluate the clinical efficacy of intradermal acupuncture (IA) for MDD based on changes in the biological specificities of acupoints.