Response, remission and drop-out rates following high-frequency repetitive transcranial magnetic stimulation (rTMS) for treating major depression: a systematic review and meta-analysis of randomized, double-blind and sham-controlled trials

Background Meta-analyses have shown that high-frequency (HF) repetitive transcranial magnetic stimulation (rTMS) has antidepressant properties when compared with sham rTMS. However, its overall response and remission rates in major depression (MD) remain unclear. Thus, we have systematically and quantitatively assessed the efficacy of HF-rTMS for MD based on randomized, double-blind and sham-controlled trials (RCTs). Method We searched the literature from 1995 through to July 2012 using MEDLINE, EMBASE, PsycINFO, Cochrane Central Register of Controlled Trials, SCOPUS, and ProQuest Dissertations & Theses. We used a random-effects model, odds ratios (ORs) and the number needed to treat (NNT). Results Data from 29 RCTs were included, totaling 1371 subjects with MD. Following approximately 13 sessions, 29.3% and 18.6% of subjects receiving HF-rTMS were classified as responders and remitters, respectively (compared with 10.4% and 5% of those receiving sham rTMS). The pooled OR was 3.3 (p<0.0001) for both response and remission rates (with associated NNTs of 6 and 8, respectively). Furthermore, we found HF-rTMS to be equally effective as an augmentation strategy or as a monotherapy for MD, and when used in samples with primary unipolar MD or in mixed samples with unipolar and bipolar MD. Also, alternative stimulation parameters were not associated with differential efficacy estimates. Moreover, baseline depression severity and drop-out rates at study end were comparable between the HF-rTMS and sham rTMS groups. Finally, heterogeneity between the included RCTs was not statistically significant. Conclusions HF-rTMS seems to be associated with clinically relevant antidepressant effects and with a benign tolerability profile.