This is a randomized, double-blind, sham-controlled study using transcranial Direct Current Stimulation (tDCS) for 4-week treatment. After the intervention of tDCS, there is a follow up visit at week 8 in order to understand the long-term effects of tDCS. Participants were randomly assigned 1:1 to tDCS group or sham-control group. Active tDCS comprised 20 min sessions of 2 mA direct current delivered over the dorsolateral prefrontal cortex, 5 days per week, for 4 weeks. Sham was administered similarly, but with current turned off after 30s. Apart from studying the effects of tDCS on severity of depression and cognitive function, the secondary outcomes are to examine biomarkers related to inflammatory activity. Scale assessments are performed before the initiation of treatment, week 1, week 2, week 3, week 4 and week8. Collection of blood, excrement and saliva takes place at three time points, at the baseline, week 4 and week 8.
