Clinical effectiveness of non-TMS neurostimulation in depression: Clinical trials from 2010 to 2020.

Objective: Treatment for major depressive disorder (MDD) have evolved, although there is still a strong unmet need for more effective and tolerable options. The present study summarizes and discusses recent evidence regarding the non-transcranial magnetic stimulation (non-TMS) neurostimulation treatment for MDD.

Methods: The authors reviewed non-TMS neurostimulation clinical trials for MDD between 2010 and 2020. Electroconvulsive therapy was not included in this review. A systematic review was performed in MEDLINE database through PubMed, the Cochrane Collaboration's Clinical Trials Register (CENTRAL), PsycINFO and Thomson Reuters's Web of Science.

Results: Only 20 articles met the inclusion criteria. Randomized controlled trials demonstrated efficacy of transcranial direct current stimulation (tDCS) in five of seven trials. tDCS augmented with sertraline, fluoxetine, citalopram and escitalopram was superior to placebo and to tDCS only. A comparative trial demonstrated that the duration of tDCS sessions can modulate the effectiveness of this treatment. Open trials indicated that deep brain stimulation, epidural cortical stimulation, trigeminal nerve stimulation, magnetic seizure therapy and vagus nerve stimulation may be effective in treatment-resistant depression.

Conclusion: This review confirmed the efficacy of tDCS in MDD. Despite new evidence showing effectiveness for other non-TMS neurostimulation, their effectiveness is still unclear. Non-TMS neurostimulation RCTs with large samples and head-to-head studies comparing non-TMS neurostimulation and gold standard pharmacological treatments are still lacking.