OBJECTIVE: Transcranial magnetic stimulation (TMS) is a noninvasive and easily
tolerated method of altering cortical physiology. The authors evaluate evidence
from the last decade supporting a possible role for TMS in the treatment of
depression and explore clinical and technical considerations that might bear on
treatment success. METHOD: The authors review English-language controlled
studies of nonconvulsive TMS therapy for depression that appeared in the MEDLINE
database through early 2002, as well as one study that was in press in 2002 and
was published in 2003. In addition, the authors discuss studies that have
examined technical, methodological, and clinical treatment parameters of TMS.
RESULTS: Most data support an antidepressant effect of high-frequency repetitive
TMS administered to the left prefrontal cortex. The absence of psychosis,
younger age, and certain brain physiologic markers might predict treatment
success. Technical parameters possibly affecting treatment success include
intensity and duration of treatment, but these suggestions require systematic
testing. CONCLUSIONS: TMS shows promise as a novel antidepressant treatment.
Systematic and large-scale studies are needed to identify patient populations
most likely to benefit and treatment parameters most likely to produce success.
In addition to its potential clinical role, TMS promises to provide insights
into the pathophysiology of depression through research designs in which the
ability of TMS to alter brain activity is coupled with functional neuroimaging.