Transcranial direct cranial stimulation (tDCS) is a novel technique based on the application of a weak electrical current over the scalp through two electrodes - the anode, which facilitates neuronal depolarization, and the cathode, which leads to neuronal hyper-polarization. Recently, several open-label and sham-controlled clinical trials applied daily tDCS sessions for the treatment of major depressive disorder (MDD). Theoretically, tDCS displays depression improvement through anodal stimulation over the left dorsolateral prefrontal, inducing excitability-enhancing effects over this area, which is hypoactive during the acute depressive episode. The present study is aimed at comparing two different tDCS protocols: (1) active anodic stimulation over left dorsolateral prefrontal cortex with cathode placed over an extra cephalic area; (2) active cathode placed over the right dorsolateral prefrontal cortex with anode placed over an extra cephalic area.