DURABILITY OF THE ANTIDEPRESSANT EFFECT OF THE HIGH-FREQUENCY REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION (rTMS) IN THE ABSENCE OF MAINTENANCE TREATMENT IN MAJOR DEPRESSION: A SYSTEMATIC REVIEW AND META-ANALYSIS OF 16 DOUBLE-BLIND, RANDOMIZED, SHAM-CONTR

Background The aim of the current meta-analysis was to investigate predictors of the durability of the antidepressant effect of high-frequency (>1 Hz) repetitive transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex in the absence of active maintenance treatment. Methods Following a systematic literature search of Medline and PsycInfo, N = 16 double-blind, parallel-design, randomized-controlled trials (RCTs) with high-frequency rTMS and inactive sham were included in the current meta-analysis. The effect size (Cohen's d) was the standardized mean difference in depression scores between sham and rTMS groups (baseline –follow-up). Meta-analysis was conducted according to a random-effects model with inverse-variance weights. Results Most RCTs reported only short follow-up phases of 2 weeks (range of 1–16 weeks). The antidepressant effect was observed during follow-up (in the absence of maintenance treatment) compared to baseline (overall mean weighted d = –.48, 95% confidence interval: –.70, –.25, P < .001, N = 16 RCTs with 495 patients). Such an antidepressant effect during follow-up was higher in RCTs with patients who were less severely ill, unipolar, nonpsychotic, treatment-resistant, and on antidepressants (either started with rTMS or continued at stable doses during acute treatment phases). The effect sizes were lower in RCTs with longer (8–16 weeks) compared to shorter (1–4 weeks) follow-up periods. The risk of publication bias was low. Conclusions High-frequency rTMS has only a small antidepressant effect during follow-up after short acute treatment (5–15 sessions) in the absence of active maintenance treatment. This effect depends on illness severity, decreases over time, and appears to be enhanced by antidepressants.