Cognitive Enhancement on Working Memory in Patients With Schizophrenia

Right DLPC was located as F4 according to the international 10-20 EEG system. Anodal tDCS was delivered with the anodal pole on the right DLPFCand the cathodal pole on the left cheek of the participant to avoid contaminating other brain regions during electrical stimulation via a pair of rubber electrodes housed in saline-soaked sponge coverings (5x5 cm\^2). The direct current was applied with 1.5 mA for 15 min which can facilitate visual short-term memory and create an excitatory effect for up to 90 min. The anodal tDCS stimulated the right DLPC for 15 min with 1.5 mA in active tDCS condition. The sham tDCS condition followed identical tDCS protocol and same 15-min duration except the stimulation time only lasted for the initial 30s so that the participants felt the same initial tingling sensation (if any, only in some participants) but without the actual stimulation. The investigators will perform assessments of adverse effects after each session by a standardized questionnaire.