Changes in neuroplasticity and cortical excitability in patients with schizophrenia undergoing Transcranial Direct Current Stimulation (tCDS): a literature review

Beatriz do Nascimento Garcia Moreno1, Blenda Antunes Cacique Curcino de Eça1, Daniel Fernandes Silva Marques1, Lorena Silva dos Reis1, Maria Clara Rêgo de Araújo1, Teresa Neves da Rocha Correia1

1Estudantes de Medicina da Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia, Brasil

OBJECTIVE: To describe the main changes in neuroplasticity and cortical excitability in patients with schizophrenia treated with Transcranial Direct Current Stimulation (tDCS).

METHODS: In order to carry out a literature review, scientific articles were searched in the PUBMED database, in which only articles in English with primary data were considered, without year restriction, resulting in the following research formula: “ (((((("direct current stimulation") OR "tdcs") AND "schizophrenia") AND "cortical excitability")) OR ((((("direct current stimulation") OR "tDCS") AND "schizophrenia") AND "neuroplasticity") ”.”

RESULTS: 30 articles were found, of which only seven - published between 2011 and 2020 - met the eligibility criteria, among them were 3 case reports, 3 clinical trials and 1 proof of concept. A proof of concept and a clinical trial showed that short-term intracortical inhibition (SICI) increased due to modulation of the left cortex after performing active tCDS. Just like one of the case reports suggested that neuroplasticity genes like NRG1 and COMT may negatively affect the changes induced by tCDS in patients with auditory hallucinations. As for changes in Δ-N100, it is observed that the use of tCDS increased its amplitude, reducing auditory hallucinations.

CONCLUSIONS: The use of tCDS revealed changes in neuroplasticity and cortical excitability through the influence of gene mutations. Despite favorable points for the use of tCDS, the studies cited were neither randomized nor developed on a large scale, which encourages us to seek more knowledge about this topic

KEYWORDS: schizophrenia; transcranial direct current stimulation; tCDS; neuroplasticity; cortical excitability.