Sixty patients will be divided into four groups: 1) 15 schizophrenic subjects in a tDCS treatment group; 2) 15 schizophrenic subjects in a sham tDCS group; 3) 15 healthy subjects in a tDCS treatment group; 4) 15 healthy subjects in a sham tDCS group. All participants will complete baseline tests including an n-back test, the Hayling test and metaphoric comprehension test. The schizophrenic subjects only, will complete a bank of cognitive tests as a baseline (MATRICS Consensus Cognitive Battery (MCCB). The first meeting for the schizophrenic subjects only will be used to determine the best stimulation area (right/left DLPFC) and type (anodal/ cathodal). Schizophrenic subjects in both the treatment and the control groups will undergo six treatment sessions in total. The cognitive tests will be given to all participants once again at the end of the study. In order to evaluate improvement between the pre-test and the post-test, differences in reaction times and error rate will be calculated for each participant.