Repetitive Transcranial Magnetic Stimulation for Major Depressive Disorder: A Review

Abstract

Several studies demonstrated that repetitive transcranial magnetic stimulation (rTMS) is an efficacious treatment for treatment-resistant major depressive disorder (TRD). Recent metaanalyses and more recent large multicentre studies provided evidence suggesting that rTMS is indeed a promising treatment; however, its efficacy has often been shown to be modest, compared with sham stimulation. We review these lines of evidence and discuss several reasons that may explain the modest therapeutic efficacy in most of these studies, including: most involved left-sided treatment alone to the dorsolateral prefrontal cortex (DLPFC) only, which may be less optimal than applying bilateral stimulation; suboptimal methods were used to target the DLPFC (that is, the 5-cm anterior method), limiting the treatment potential of inherently a targeted form of treatment; some treatment durations were short (that is, 2 to 4 weeks); and stimulation intensity might have been insufficient by not considering coil-to-cortex distance, which has been linked to rTMS-induced antidepressant response. Future studies attempting to address the above-mentioned limitations are necessary to potentially optimize the efficacy of this already promising treatment option in TRD. Finally, it is also essential that research investigate the mechanisms of therapeutic efficacy, thus increases in understanding can be translated into enhanced treatment. For several reasons that will be reviewed, cortical excitability may represent an important mechanism, linked to the therapeutic efficacy of this disorder.

Using neuroimaging to individualize TMS treatment for depression: Toward a new paradigm for imaging-guided intervention

“…However, despite its increasing use, typical effect sizes of rTMS treatment have been modest (Berlim et al, 2014; Lefaucheur et al, 2014), and both methodological and conceptual challenges remain regarding how to optimize its efficacy (Downar and Daskalakis, 2013; Daskalakis et al, 2008). This review considers two such challenges: specifically, targeting and context of stimulation.…”

Impaired Prefronto-Thalamic Functional Connectivity as a Key Feature of Treatment-Resistant Depression: A Combined MEG, PET and rTMS Study

“…Some patients with TRD can nonetheless manifest good responses to repetitive transcranial magnetic stimulation (rTMS) treatment [5]–[8], particularly when a combination of daily prefrontal rTMS and medication treatment was applied for weeks [8]. Hypoexcitability over the left prefrontal cortex (PFC) and hyperexcitability over the right PFC are commonly-accepted mechanisms to be associated with depression [5], which could explain why the initial use of the excitatory rTMS (e.g., 10 Hz) applied to the left PFC and the inhibitory rTMS (e.g., 1 Hz) to the right PFC in TRD [5].…”

Unanticipated Rapid Remission of Refractory Bulimia Nervosa, during High-Dose Repetitive Transcranial Magnetic Stimulation of the Dorsomedial Prefrontal Cortex: A Case Report

“…Repetitive transcranial magnetic stimulation (rTMS) is an emerging option in the treatment of refractory depression (Daskalakis et al, 2008; Lam et al, 2008; Schonfeldt-Lecuona et al, 2010). To date, few studies have examined the use of rTMS in patients with eating disorders, and results have been mixed using the conventional rTMS target in the dorsolateral prefrontal cortex (DLPFC; Hausmann et al, 2004; Walpoth et al, 2008; Van den Eynde et al, 2010).…”