Application of stellate ganglion modulation in mental disorders and the future prospects of physical therapies.

The treatment of mental disorders faces significant challenges due to their complex etiology and the limitations of existing therapies. Neuromodulation has emerged as a promising approach for managing these conditions. Among the various neuromodulatory strategies, stellate ganglion modulation (SGM) specifically targets the sympathetic nervous system by inhibiting neural activity at the cervical stellate ganglion (SG). Stellate ganglion block (SGB), a chemical form of SGM achieved through local anesthetic injection into the SG, suppresses sympathetic nerve impulses to the head, neck, and upper limbs. Evidence suggests that SGB offers a favorable safety profile and demonstrates notable efficacy in treating post-traumatic stress disorder. Moreover, preliminary findings indicate its potential in managing depression and sleep disorders. Current hypotheses propose that SGB alleviates psychological symptoms via two pathways: ascending regulation, which modulates neuroendocrine activity and neuroinflammation, and descending regulation, which influences cardiovascular and digestive functions, thereby engaging the heart-brain and gut-brain axes. Recently, physical energy-based modalities for SGM, including electrical, magnetic, optical, thermal, and ultrasonic stimulation, have been explored as alternatives to conventional chemical modulation. Invasive physical methods such as electroacupuncture and radiofrequency ablation show preliminary efficacy and safety, while noninvasive approaches provide simpler and safer options, with some evidence of benefit in conditions such as arrhythmia. However, clinical validation in psychiatric populations remains limited. Despite the therapeutic promise of physical SGM, key questions persist regarding its mechanisms, efficacy, and safety in mental disorders. Future research should aim to expand preclinical studies, verify these techniques in psychiatric populations, standardize stimulation parameters, develop closed-loop feedback systems, and assess long-term outcomes.