Efficacy and tolerability of deep transcranial magnetic stimulation for treatment-resistant depression: A systematic review and meta-analysis

Objectives: This study aimed to investigate the efficacy of deep transcranial magnetic stimulation (dTMS) for treatment-resistant depression (TRD). Methods: This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Medline, PsycINFO, Embase, and Cochrane Library were systematically searched from the time of their inception until July 17, 2019. Data were pooled using a random-effects model. Primary outcomes were mean change of depression and anxiety severity. Secondary outcomes were response and remission rate of depression. Results: Fifteen studies including three randomized controlled trials (RCTs) (n = 417, mean age: 50.6 years) and twelve uncontrolled clinical trials (n = 284, mean age: 46.4 years) were included. dTMS significantly improved the depressive (Hedges' g = -1.323, 95% CI = -1.651 to - 0.995, p < .001) and anxiety symptoms (Hedges' g = -1.282, 95% CI = -1.514 to - 1.051, p < .001) in patients with TRD. Subgroup analysis showed that non-RCTs had a larger effect size than RCTs (-1.461 vs - 0.756) on depression severity. Although the response and remission rates of the dTMS group were high, only studies using both dTMS and antidepressant medications achieved significance. The anxiolytic effect of dTMS was more heterogeneous, and the results were obtained mainly from non-RCTs. Importantly, the dTMS group showed favorable tolerability without major adverse events. Conclusions: dTMS is a safe and effective intervention in patients with TRD. Studies combining dTMS and antidepressant medications seemed to show greater therapeutic effects. Future studies are needed to address the interaction effect of dTMS with different classes of antidepressant medications.