Abstract
BACKGROUND: Subthreshold depression (SD), characterized by depressive symptoms not meeting major depressive disorder (MDD) criteria, poses a significant risk for MDD development. Acupuncture has shown promise for SD, though its efficacy beyond placebo remains unclear. Therefore, we designed this study to evaluate the efficacy of verum acupuncture (VA) compared to sham acupuncture (SA) for SD. METHODS: A randomized clinical trial was conducted at the Affiliated Hospital of Shandong University of Traditional Chinese Medicine, China, from September 2021 to October 2023. Participants with SD were randomized 1:1 to receive either VA or SA for 8 weeks, with 12-week follow-up. The primary outcome was the change in Hamilton Depression Scale-17 (HAMD-17) scores from baseline to 8 weeks. RESULTS: Of 231 screened patients, 64 participants (71.87% female; mean age, 29.83 [SD 6.84] years) were included. Fifty-nine participants (92.2%) completed the study. The mean reduction in HAMD-17 scores from baseline to week 8 was -7.28 (95% CI, -8.26 to -6.3) in the VA group and -3.80 ( 95% CI, -4.42 to -2.77) in the SA group. The between-group difference at week 8 was -4.08 (95% CI, -5.15 to -3.02; P < .001). Effects persisted during the 12-week follow-up. No serious adverse events occurred. CONCLUSIONS: Acupuncture demonstrated significant therapeutic effects for SD compared to SA, with benefits extending beyond placebo. These findings support acupuncture as a specific and effective intervention for SD. However, the study's limitations, including its single-center design and relatively young sample, should be considered when generalizing the results. TRIAL REGISTRATION: ChiCTR2100049660; Registered August 7, 2021.