Is transcranial direct current stimulation, alone or in combination with antidepressant medications or psychotherapies, effective in treating major depressive disorder? A systematic review and meta-analysis

Abstract

Background Transcranial direct current stimulation (tDCS) has shown mixed results for depression treatment. The efficacies of tDCS combination therapies have not been investigated deliberately. This review aims to evaluate the clinical efficacy of tDCS as a monotherapy and in combination with medication, psychotherapy, and ECT for treating adult patients with major depressive disorder (MDD) and identified the factors influencing treatment outcome measures (i.e. depression score, dropout, response, and remission rates). Methods The systematic review was performed in PubMed/Medline, EMBASE, PsycINFO, Web of Sciences, and OpenGrey. Two authors performed independent literature screening and data extraction. The primary outcomes were the standardized mean difference (SMD) for continuous depression scores after treatment and odds ratio (OR) dropout rate; secondary outcomes included ORs for response and remission rates. Random effects models with 95% confidence intervals were employed in all outcomes. The overall effect of tDCS was investigated by meta-analysis. Sources of heterogeneity were explored via subgroup analyses, meta-regression, sensitivity analyses, and assessment of publication bias. Results Twelve randomised, sham-controlled trials (active group: N = 251, sham group: N = 204) were included. Overall, the integrated depression score of the active group after treatment was significantly lower than that of the sham group (g = − 0.442, p = 0.017), and further analysis showed that only tDCS + medication achieved a significant lower score (g = − 0.855, p < 0.001). Moreover, this combination achieved a significantly higher response rate than sham intervention (OR = 2.7, p = 0.006), while the response rate remained unchanged for the other three therapies. Dropout and remission rates were similar in the active and sham groups for each therapy and also for the overall intervention. The meta-regression results showed that current intensity is the only predictor for the response rate. None of publication bias was identified. Conclusion The effect size of tDCS treatment was obviously larger in depression score compared with sham stimulation. The tDCS combined selective serotonin re-uptake inhibitors is the optimized therapy that is effective on depression score and response rate. tDCS monotherapy and combined psychotherapy have no significant effects. The most important parameter for optimization in future trials is treatment strategy.

Home-based transcranial direct current stimulation in dual active treatments for symptoms of depression and anxiety: A case series

“…Although the results of dual active treatments of tDCS with antidepressants are conflicting [e.g., lower depression scores and higher response rates (33) vs reduced antidepressant effect of tDCS when combined with benzodiazepines (34, 35)], warranting new clinical studies to unveil treatment parameters, the potential benefit of tDCS combined with antidepressants was preliminarily observed in our patients 4 and 7, with a reduction of depression and anxiety scores. Moreover, our findings seem to contrast with the literature reporting the lack of effect of tDCS combined with psychotherapy (33) which might be due to differences in stimulation parameters. The observed improvements during the maintenance phase are also in accordance with dosage-dependent tDCS effects and the need for short intervals in the post-acute treatment of depression (36-38), suggesting that longer treatment courses may lead to optimal results (5).…”

Augmenting cognitive training with bifrontal tDCS decreases subclinical depressive symptoms in older adults: Preliminary findings

“…Transcranial direct current stimulation (tDCS) applied to the frontal lobe, either in isolation or as augmentation to another treatment, has antidepressant properties in depressed adults [1]. Pairing tDCS with cognitive training (CT) results in additional benefit [2,3].…”

Therapeutic potential of brain stimulation techniques in the treatment of mental, psychiatric, and cognitive disorders

“…Several meta‐analysis studies suggest that the application of tDCS has antidepressant effects 82–84 and this effect can last for long‐term 85 . In addition, an application of tDCS combined with either antidepressant medications or psychotherapy was more effective treatment for depression than tDCS alone 86–88 . The effectiveness of behavioral therapy in combination with tDCS was also observed in relieving patients from depression 89,90 …”