Transcranial Direct Current Stimulation in Patients with Anxiety: Current Perspectives

Dirson João Stein, 1, 2,* Liciane Fernandes Medeiros, 1, 3, 4,* Wolnei Caumo, 2 Iraci LS Torres 1– 3 1Laboratório de Farmacologia da Dor e Neuromodulação, Investigações Pré-Clínicas, Centro de Pesquisa Experimental, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil; 2Programa de Pós-Graduação em Medicina: Ciências Médicas, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; 3Programa de Pós-Graduação em Ciências Biológicas: Farmacologia e Terapêutica, UFRGS, Porto Alegre, RS, Brazil; 4Programa de Pós-Graduação em Saúde e Desenvolvimento Humano, Universidade La Salle, Canoas, RS, Brazil*These authors contributed equally to this workCorrespondence: Iraci LS TorresPharmacology Department, ICBS, UFRGS, Rua Sarmento Leite, 500 - Sala 237, 90.050-170, Porto Alegre, RS, BrazilTel +55 51 3308 3183Fax +55 51 3308 3121Email iltorres@hcpa.edu.brAbstract: Anxiety is one of the most prevalent and debilitating psychiatric conditions worldwide. Pharmaco- and psycho-therapies have been employed in the treatment of human anxiety to date. Yet, either alone or in combination, unsatisfactory patient outcomes are prevalent, resulting in a considerable number of people whose symptoms fail to respond to conventional therapies with symptoms remaining after intervention. The demand for new therapies has given birth to several noninvasive brain stimulation techniques. Transcranial direct current stimulation (tDCS) has arisen as a promising tool and has been proven to be safe and well tolerated for the treatment of many diseases, including chronic pain, depression, and anxiety. Here, reports of the use of tDCS in anxiety disorders in human patients were reviewed and summarized. A literature search was conducted in mid-2019, to identify clinical studies that evaluated the use of tDCS for the treatment of anxiety behavior. The PubMed, Web of Science, and Scielo and PsycInfo databases were explored using the following descriptors: “anxiety”, “anxious behavior”, “tDCS”, and “transcranial direct current stimulation”. Among the selected articles, considerable variability in the type of tDCS treatment applied in interventions was observed. Evidence shows that tDCS may be more effective when used in combination with drugs and cognitive behavioral therapies; however future large-scale clinical trials are recommended to better clarify the real effects of this intervention alone, or in combination with others.Keywords: transcranial electrical stimulation, psychiatric disorder, anxious behavior, humans, clinical research