Can transcranial direct current stimulation (tDCS) alleviate symptoms and improve cognition in psychiatric disorders?

Objectives. Since the discovery of psychopharmacological treatments in the early 1950s, followed by the development of second-generation antidepressants and antipsychotics, biological psychiatry has not achieved much progress. Recent technological advances in the field of non-invasive brain stimulation open new perspectives in the treatment of psychiatric disorders. Amongst them, transcranial direct current stimulation (tDCS) modulates cortical excitability and induces long-lasting effects. Here, we aimed at evaluating whether tDCS has potential to be developed as an innovative treatment in psychiatry. Methods. We conducted a systematic review of the current state of development and application of tDCS in psychiatric disorders, exploring clinical and cognitive effects, especially in major depressive disorder (MDD), schizophrenia and substance use disorder. Results. Systematic literature search yielded 40 publications: 22 in MDD, nine in schizophrenia, seven in substance use disorder, one in obsessive -compulsive disorder and one in mania. Our findings indicated beneficial clinical effects of tDCS for MDD and a promising literature in schizophrenia and substance use disorder. Conclusions. Despite methodological differences, the data published to date are promising and supports the use of tDCS as a treatment for psychiatric disorders. However, its place regarding other treatments still has to be determined before becoming a routine clinical treatment.