Neuromodulation therapies and treatmentresistant depression

Background: Patients with treatment-resistant depression (TRD) who showed partial response to pharmacological and psychotherapeutic interventions need a trial of neuromodulation therapies (NTs). Objective: This paper aims to review evidence-based data on the use of NTs in TRD. Method: Using keywords and combined-word strategy, multiple computer searches of PubMed, Google Scholar, Quertle(R), and Medline were conducted for retrieving relevant articles published in English-language peer-reviewed journals (2000-2012). Those papers that addressed NTs in TRD were retained for extensive review. Results: Despite methodological challenges, a range of 30%-93% of TRD patients showed substantial improvement to one of the NTs. One hundred-percent improvement was reported in two single-case studies on deep brain stimulation. Some studies reported no benefits from transcranial direct current stimulation. NTs were reported to have good clinical efficacy, better safety margin, and benign side-effect profile. Data are limited regarding randomized clinical trials, long-term efficacy, and cost-effectiveness of these approaches. Both modified electroconvulsive therapy and magnetic seizure therapy were associated with reversible but disturbing neurocognitive adverse effects. Besides clinical utility, NTs including approaches on the horizon may unlock the biological basis underlying mood disorders including TRD. Conclusion: NTs are promising in patients with TRD, as the majority of them show good clinical response measured by standardized depression scales. NTs need further technological refinements and optimization together with continuing well-designed studies that recruit larger numbers of participants with TRD.