Why this study matters

Between 20% and 30% of patients with MDD do not have satisfactory responses to CBT, pharmacotherapy, or a combination of the two.

Given the multifactorial pathogenesis underlying MDD, targeting more than one putative pathogenic process in MDD patients refractory to treatment (i.e., augmenting a single treatment modality, such as combining CBT with tDCS) may improve the treatment response and remission.

Study design

A double-blind, placebo-controlled randomized clinical trial was conducted involving 6 German university hospitals.

Eligible participants were 20-65 years of age with a single episode or recurrent episodes of depression who were either receiving no medications or were on a stable medication regimen (n=148).

The patients were assigned to CBT alone, CBT + tDCS, or CBT + sham-tDCS groups. The patients were treated for 6 weeks (2 CBT sessions per week with or without tDCS or sham-tDCS at each CBT session).

The treatment effect was assessed based on the pre- and post-treatment Montgomery-Asberg Depression Rating Scale (MADRS) scores.

Results and conclusion

The 89 women and 59 men enrolled in the study, 126 completed the study and had a mean pre-treatment MADRS score of 23.0. Treatment reduced the pre-treatment MADRS score by a mean of 6.5 points in each of the 3 groups.

There were no significant treatment effect differences between the groups, thus tDCS did not have an additive effect on CBT alone.