 Major Depressive Disorder MDD is a common mental disorder, with a lifetime prevalence of 15 and an incidence of 5 per year. Its core symptoms include lack of pleasure in daily activities, thoughts of guilt and depressed mood. According to the World Health Organization, MDD is one of the ten most impairing conditions, leading to missing workdays, loss of quality of life and increasing expenses in health care. Besides, about 1 of patients with MDD complete suicide. Moreover, one third of patients with MDD remain depressed after more than two adequate treatments, i.e., they are refractory to conventional antidepressant treatments; also, most treated patients remain with residual symptoms. Therefore, the development of new treatments is necessary. Transcranial direct current stimulation tDCS is a novel, promising technique in the study of several neuropsychiatric conditions. 