Abstract
Transcranial magnetic stimulation (TMS) is a very convenient technique to stimulate the central nervous system noninvasively, almost painlessly. The repetitive TMS (rTMS) has developed for many years and many studies about the antidepressant effect of rTMS have been performed. And it has recently been licensed in some countries for the treatment of depression. Furthermore, rTMS has been applied for other psychiatric diseases such as schizophrenia and manic state. Nevertheless, it remains unclear that rTMS is conclusively effective in treating depression. This might be the reason why it has not yet become common tool for the treatment of depressive disorder in Japan. In this study, we performed clinical trials of high-frequency rTMS (20 Hz) for the treatment of refractory depression. We also measured plasma levels of catecholamine metabolites and brain-derived neurotrophic factor (BDNF) to clarify the mechanism of the action of rTMS in the treatment of depression. Twenty-six depressed patients who met the DSM-IV criteria for major depressive disorder participated in this study. Eleven were male, fifteen female. All patients were given left prefrontal 20 Hz rTMS at 80% motor threshold (MT) over ten daily sessions. The mean 17-item Hamilton Rating Scale for Depression (Ham-D) score of 20.5±5.2 before rTMS decreased significantly to 15.6±7.3 after rTMS. Nine of 26 patients demonstrated some improvement (Ham-D≥25%) after rTMS. The levels of plasma MHPG were significantly reduced after rTMS treatment, and it was observed that the change in plasma MHPG levels had a negative correlation with the change in scores of agitation. Furthermore the plasma levels of BDNF were significantly increased in responders andpartial responders, but not in nonresponders, after rTMS treatment. These results suggest that rTMS treatment brings about some improvement in refractory depression, especially in depression with symptoms such as agitation.
