Effects of acupuncture on brain function in patients with depression: A meta-analysis of functional magnetic...

Depression poses a major global health burden. Many patients exhibit treatment resistance or experience intolerable side effects with standard therapies. Acupuncture shows promise as an adjunctive therapy for depression, but its neurobiological mechanisms remain incompletely understood.

We conducted a coordinate-based meta-analysis to identify consistent patterns of acupuncture-induced neuroplastic changes in patients with major depressive disorder, quantified via resting-state functional magnetic resonance imaging measures of regional homogeneity and amplitude of low-frequency fluctuations (ALFF/fractional ALFF). We synthesized data from 7 randomized controlled trials involving 357 patients with major depressive disorder, comparing acupuncture-based interventions (manual acupuncture, electroacupuncture, or transcutaneous auricular vagus nerve stimulation) against sham acupuncture, conventional treatment, or treatment-as-usual. The seed-based d mapping with permutation of subject images algorithm was used for the imaging meta-analysis, and a leave-one-out sensitivity analysis was performed to assess the robustness of the pooled findings to intervention heterogeneity.

Acupuncture induced significant regional homogeneity /ALFF increases within the right cingulum and right caudate nucleus. In contrast, conventional treatments primarily increased activity in the left hippocampus and right middle occipital gyrus. Meta-regression linked clinical improvement specifically to plasticity changes in the left cerebellum and revealed a dose-dependent relationship between the number of acupuncture sessions and modulation of the left amygdala. Clinically, acupuncture produced significantly greater reductions in depression and anxiety scores than control conditions.

Our findings indicate that acupuncture-based interventions elicit a distinct pattern of neuroplastic remodeling, targeting key regions involved in emotion regulation and reward processing, which contrasts with the hippocampal-occipital effects of conventional treatments. The correlation between neuroplastic changes in affective circuits and clinical improvement supports a potential mechanism for acupuncture's efficacy in alleviating core depressive symptoms such as anhedonia and emotional dysregulation. Limitations include the small number of included trials, heterogeneity in acupuncture protocols and resting-state functional magnetic resonance imaging metrics, absence of long-term follow-up data, and methodological caveats inherent to coordinate-based meta-analysis. Future research requires larger, standardized trials with follow-up assessments and integration of neuroimaging with molecular biomarkers to advance personalized neuromodulation strategies for depression.