Mechanisms and clinical applications of acupuncture in treating somatic symptoms of depression: a review

This comprehensive systematic review examines the neurobiological mechanisms and clinical efficacy of acupuncture in treating somatic symptoms associated with depression, an area of growing clinical interest given the limitations of conventional pharmacologic treatments. Depression frequently presents with significant physical manifestations, including sleep disturbances, chronic pain, fatigue, and gastrointestinal discomfort, which substantially impact patients' quality of life and may predict worse therapeutic outcomes. The authors analyzed 107 studies, including 42 randomized controlled trials, providing a robust foundation for their conclusions about the benefits of acupuncture in this specific clinical context.

From a mechanistic standpoint, the review demonstrates that acupuncture exerts therapeutic effects through multiple interconnected neurobiological pathways. Modulation of neurotransmitters represents a central mechanism, with consistent evidence showing that acupuncture increases serum levels of serotonin, dopamine, and norepinephrine — neurotransmitters critical to mood regulation and somatic symptoms. Functional neuroimaging studies have revealed that acupuncture modulates the activity and connectivity of specific brain regions implicated in depression, including the prefrontal cortex, anterior cingulate cortex, and limbic-cortical-striatal-pallidal-thalamic circuits. These neurofunctional changes correlate with clinical improvements in depressive and somatic symptoms.

The study also highlights innovative epigenetic mechanisms, particularly the capacity of acupuncture to reduce DNA methylation at the BDNF (brain-derived neurotrophic factor) gene promoter, resulting in greater expression of this protein essential for neuroplasticity. This molecular mechanism may explain the lasting effects of acupuncture on the functional recovery of neural circuits involved in mood regulation. Additionally, acupuncture demonstrates significant anti-inflammatory properties, reducing pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α, which are elevated in depression and contribute to somatic symptoms.

The clinical results presented are consistently positive across different patient populations. In adolescents with depression, acupuncture showed significant efficacy in reducing depressive symptoms and improving sleep quality, with 4-week protocols demonstrating measurable neurobiochemical changes. In patients with treatment-resistant depression and bipolar disorder, 12-week longitudinal studies revealed improvements in physical symptoms such as cervical pain and insomnia, along with enhanced quality-of-life metrics. Acupuncture also showed benefits in special conditions such as postpartum depression, cardiac neuroses, and dry eye syndrome associated with anxiety and depression.

The treatment protocols analyzed suggest an optimal duration of 4-12 weeks, with a frequency of 1-3 weekly sessions, with higher frequency recommended in the initial phases to accelerate therapeutic response. Acupoint selection follows both standardized protocols and individualized approaches based on traditional Chinese medicine syndrome differentiation. Points such as Baihui (GV-20), Sanyinjiao (SP-6), Taichong (LR-3), Neiguan (PC-6), and Shenmen (HT-7) are frequently used for their properties in regulating the shen (mind) and hepatic and cardiac function.

The safety profile of acupuncture is consistently favorable, with adverse events rare and primarily limited to transient localized discomfort. This contrasts beneficially with the significant side effects frequently associated with pharmacologic antidepressants. The combination of acupuncture with antidepressant medication demonstrated efficacy superior to pharmacologic treatment alone, suggesting synergistic effects that may optimize clinical outcomes while minimizing drug-related adverse effects.