Repetitive transcranial magnetic stimulation : does it have potential in the treatment of depression?
Padberg F, Moller HJ.
CNS Drugs. 2003;17(6):383-403.

Transcranial magnetic stimulation (TMS) has become a major research tool in
experimental clinical neurophysiology as a result of its potential to
noninvasively and focally stimulate cortical brain regions. Currently, studies
are being conducted to investigate whether repetitive TMS (rTMS)-mediated
modulation of cortical function may also provide a therapeutic approach in
neurological and psychiatric disorders. Preclinical findings have shown that
prefrontal rTMS can modulate the function of fronto-limbic circuits, which is
reversibly altered in major depression. rTMS has also been found to exert
effects on neurotransmitter systems involved in the pathophysiology of major
depression (e.g. stimulates subcortical dopamine release and acts on the
hypothalamic pituitary adrenal axis, which is dysregulated in depression).To
date, numerous open and controlled clinical trials with widely differing
stimulation parameters have explored the antidepressant potential of rTMS.
Though conducted with small sample sizes, the majority of the controlled trials
demonstrated significant antidepressant effects of active rTMS compared with a
sham condition. Effect sizes, however, varied from modest to substantial, and
the patient selection focused on therapy-resistant cases. Moreover, the average
treatment duration was approximately 2 weeks, which is short compared with other
antidepressant interventions. Larger multicentre trials, which would be
mandatory to demonstrate the antidepressant effectiveness of rTMS, have not been
conducted to date.A putative future application of rTMS may be the treatment of
patients who did not tolerate or did not respond to antidepressant
pharmacotherapy before trying more invasive strategies such as electroconvulsive
therapy and vagus nerve stimulation. Theoretically, rTMS may be also applied
early in the course of disease in order to speed up and increase the effects of
antidepressant pharmacotherapy. However, this application has not been a focus
of clinical trials to date. Research efforts should be intensified to further
investigate the effectiveness of rTMS as an antidepressant intervention and to
test specific applications of the technique in the treatment of depressive




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