Repetitive transcranial magnetic stimulation: advances for psychiatric disorders

Repetitive transcranial magnetic stimulation (rTMS) has accumulated substantial exploratory evidence in the treatment of major Depressive Disorders, bipolar disorder, schizophrenia, obsessive-compulsive disorder, and generalized anxiety disorder; however, its clinical efficacy is highly dependent on the precise matching of stimulation parameters (such as frequency, intensity, total number of pulses, and treatment course) with target regions (such as the dorsolateral prefrontal cortex, supplementary motor area, temporal-parietal cortex). Key findings: In major Depressive Disorders, both high-frequency stimulation of the left dorsolateral prefrontal cortex and low-frequency stimulation of the right dorsolateral prefrontal cortex demonstrate antidepressant effects; however, efficacy is modulated by coil type, concomitant medication, and disease subtypes, and there is currently a lack of reliable closed-loop biomarker guidance for individualized treatment. Research on bipolar disorder suggests that intermittent theta burst stimulation and low-frequency right dorsolateral prefrontal cortex stimulation are effective for depressive episodes, but evidence for manic episodes is limited, necessitating the establishment of rigorous risk management mechanisms for manic conversion. In the treatment of schizophrenia, low-frequency temporo-parietal stimulation can alleviate auditory hallucinations, while improvements in negative symptoms and cognitive deficits are associated with high frequency, high intensity, long treatment duration, and younger patients; however, there is significant heterogeneity among studies. Regarding obsessive-compulsive disorder, low-frequency stimulation of the right dorsolateral prefrontal cortex, low-frequency stimulation of the supplementary motor area, and deep transcranial magnetic stimulation targeting the orbitofrontal cortex all demonstrate therapeutic potential; however, treatment efficacy shows extremely high heterogeneity (I² > 75%), and there is an urgent need to establish uniform criteria for classifying treatment resistance. Preliminary evidence for generalized anxiety disorder supports high-frequency stimulation of the right dorsolateral prefrontal cortex and bilateral combined protocols; their efficacy may involve the regulation of brain-derived neurotrophic factor and serotonin levels, but current studies have small sample sizes and the mechanisms of action remain unclear. Although these findings support the potential application of rTMS in various psychiatric disorders, current studies generally share common limitations, including insufficient sample sizes, lack of rigorous sham controls, short follow-up periods, absence of standardized parameters, and scarcity of reliable biomarkers, which severely hinder its clinical implementation. Future research urgently requires the establishment of standardized stimulation parameters and a treatment-resistance grading framework through multicenter, large-sample randomized controlled trials. It should integrate neuro-navigation with neurophysiological biomarkers (such as resting-state functional MRI and individualized alpha frequency) to achieve personalized, precision-targeted treatment, and systematically evaluate the synergistic effects of rTMS with medication and psychotherapy, as well as its long-term safety.