Meta-analysis of left prefrontal repetitive transcranial magnetic stimulation (rTMS) to treat depression.
BACKGROUND
Depression is a common and severe disorder for which new treatments are needed. Repetitive transcranial magnetic stimulation (rTMS) is a promising new treatment. The purpose of this meta-analysis was to determine whether the literature supports the use of left prefrontal rTMS as a treatment option for depression.


METHODS
The literature was searched for randomized sham-controlled trials of left prefrontal rTMS to treat depression using PsycINFO, MEDLINE, and CURRENT CONTENTS as well as two previous meta-analyses of rTMS. Using MetaWin, a Hedges' d effect size and nonparametric variances were calculated in order to determine a cumulative effect size. Tests for heterogeneity and publication bias were also calculated.


RESULTS
Twelve of fourteen studies (n = 230) were suitable for analysis. The summary analysis revealed a cumulative effect size of 0.53 (95% CI 0.24-0.82). The test for heterogeneity was not significant (Qtotal = 10.65, df = 11, Prob {chi} = 0.47). The fail-safe result using the Rosenthal's method (55.1 non-significant studies) and the Orwin's method (20.0 non-significant studies) revealed that 20 to 55 studies would have to be unavailable in order to change the cumulative effect to a non-significant result.


CONCLUSIONS
The meta-analysis supports the hypothesis that left prefrontal rTMS is an acute antidepressant treatment with statistically significant effect sizes and measurable clinical improvement.
Psychiatry Department, Medical University of South Carolina, Charleston 29425, USA.
F Andrew
FA
Kozel
Mark S
MS
George