Low frequency rTMS stimulation of the right frontal cortex is as effective as high frequency rTMS stimulation of the left frontal cortex for antidepressant-free, treatment-resistant depressed patients

Background. Repetitive transcranial magnetic stimulation (rTMS) is a promising relatively non-invasive alternative for the treatment of depression. The purpose of this study was to compare the apparent effectiveness of high frequency (20 Hertz) rTMS applied over the left dorsolateral prefrontal cortex (DLPFC) with that of low frequency (1 Hz) rTMS applied over the right DLPFC. Methods. Twenty-eight antidepressant-free adults with major depressive (n = 25) or bipolar (n = 3) disorder (not on mood stabilizers) in a current major depression (Hamilton Rating Scale for Depression [HAM-D-21] ≥ 18; Mean = 24.5, SD = 5.51) were treated (14 right, 14 left) for 4 weeks. Results. Overall paired t-tests revealed a significant reduction in mean HAM-D-21, Beck Depression Inventory (BDI-II), and Clinical Global Impression of Change (CGIC) scores at the end of treatment for both groups (high frequency left DLPFC and low frequency right DLPFC). The treatment response rate found (32%) was typical of other response rates reported in the literature (6,30). One-month follow-up data was obtained from 50% of participants. At 1-month follow-up no significant differences were noted as compared to patients' performance at last treatment visit, indicating moderate robustness of rTMS treatment over time. Furthermore, magnetic stimulation did not substantially alter patient memory over the course of treatment. Conclusion. rTMS given at low frequency over the right frontal cortex appears to be as effective treatment of refractory depression as high frequency treatment over the left frontal cortex.