An Update about Mechanisms of Acupuncture Treatment for Mental Disorders: We Focus on Signaling Pathways, Neurotransmitters, and Neural Circuits

This article serves to summarize the mechanism of acupuncture in the treatment of mental disorders. Mental disorders currently have a wide impact, and the number of patients is increasing every year, imposing a heavy burden on the entire society. Among the current first-line treatment methods, psychotherapy is questioned due to its limited efficacy, while drug treatment often comes with adverse reactions and symptom recurrence. As a historical complementary therapy, many clinical studies have confirmed the efficacy of acupuncture in treating mental disorders. However, the treatment rules and potential mechanisms remain unclear. Through the search of literature databases, the mechanism of acupuncture in treating mental disorders was reviewed based on the criteria and classification of mental disorders in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). The mechanisms of acupuncture in treating mental disorders include anxiety, depression, substance-related and addictive diseases, insomnia, post-traumatic stress disorder, neurodevelopmental disorders, eating disorders, and sexual dysfunction. The most commonly used acupuncture points for treating mental disorders are GV20, ST36, and HT7. The included acupuncture techniques include traditional retention, electro-acupuncture, hand acupuncture, laser acupuncture, and drug-acupuncture. At present, the research on acupuncture treatment for mental disorders is still limited. In signaling pathways, acupuncture mainly exerts its effects by regulating those related to oxidative stress and inflammation. Regarding neurotransmitters, acupuncture influences glutamate, γ-aminobutyric acid, dopamine (DA), and 5-hydroxytryptamine, as well as their receptors. On the neural circuits, acupuncture exerts its effects by regulating the corresponding brain regions associated with mental disorders, such as the anterior cingulate cortex, nucleus accumbens, amygdala, and hypothalamic paraventricular nucleus related to anxiety, as well as the prefrontal cortex, nucleus accumbens, ventral tegmental area of the midbrain, and hypothalamic arcuate nucleus related to addiction disorders. Acupuncture exerts its therapeutic effect on mental disorders mainly through the regulation of signaling pathways, neurotransmitters, and neural circuits.