Introduction: Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive and easily
tolerated method of altering cortical physiology. To date, numerous open and sham
controlled clinical trials have explored the antidepressant potential of rTMS. In
the present study, we investigated clinical trials of high-frequency rTMS (20 Hz)
for treatment of refractory depression, and also examined the effect of rTMS on plasma
levels of catecholamine metabolites and brain-derived neurotropic factor (BDNF). Methods: Twenty-six depressed inpatients who met the DSM-IV criteria for major depressive
disorder and had failed to respond to treatment with at least two antidepressant drugs
given at adequate doses (above 150 mg/day in an equivalent dose of imipramine) and
durations (at least 4 weeks for each drug) were enrolled in this study. Eleven were
males, 15 females. The ages of the subjects ranged from 19 to 78 years old (mean ±
SD = 52.9 ± 17.8). All patients were administered left prefrontal 20 Hz rTMS at 80
% MT (total 800 pulses a day) over ten daily sessions. The plasma levels of 3-methoxy-4-hydroxyphenylglycol
(MHPG) and homovanillic acid (HVA) were analyzed by high-performance liquid chromatography.
The plasma levels of BDNF were also measured with the sandwich ELISA method. Results: The mean 17-item Hamilton Rating Scale for Depression (Ham-D) score of 20.5 ± 5.2
before rTMS was significantly decreased to 15.6 ± 7.3 after rTMS. Nine of 26 patients
(35 %) demonstrated some improvement (Ham-D ≥ 25 %) by rTMS. The levels of plasma
MHPG, but not those of HVA, were significantly reduced after rTMS treatment, and a
negative correlation was observed between the change in plasma MHPG levels and the
change in scores of agitation. In addition, the plasma levels of BDNF were significantly
increased by 23 % in responders and partial responders, but not in nonresponders,
after rTMS treatment, and a trend for association was found between the changes in
Ham-D scores and changes in plasma BDNF levels in all patients after rTMS treatment.
Conclusion: These results suggest that rTMS treatment brings about some improvement in refractory
depression, especially for symptoms such as agitation, by influencing MHPG and BDNF,
which is in accordance with previous reports showing that BDNF was increased by various
antidepressants treatments.
References
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Textbook of Psychiatry . 3rd edition Washington DC; American Psychiatric Press 1999: 1025-1132
yoshi621@med.uoeh-u.ac.jp
