Application of transcranial direct current stimulation to psychiatric disorders: trends and perspectives

Abstract

Growing attention is paid to transcranial direct current stimulation (tDCS) as a novel neuromodulation method in the treatment of psychiatric illnesses. In spite of its simple procedure, electrophysiological influence of tDCS is complex and not fully understood. Therefore, its procedure and clinical application is yet to be established. To address this issue, we reviewed and summarized reports currently available, and proposed future directions. We searched PubMed for the literature of tDCS, targeting depression, cognitive enhancement or schizophrenia, sham-controlled, and repeated stimulation sessions. Among psychiatric conditions, depression is most associated with positive effects of tDCS, based on the recent systematic review, due to homogeneity in methodology adopted in randomized sham-controlled trials. For cognitive enhancement and/or treatment of schizophrenia, results are less consistent, and the methods are more heterogeneous. Large-scale well-designed trials are needed to more accurately evaluate the efficacy of tDCS. In this article, considerations of optimal stimulation conditions are also provided.