The Impact of transcranial Direct Current Stimulation on Rumination: A Systematic Review of the Sham-controlled Studies in Healthy and Clinical Samples

Abstract

Objective: Broadly considered as a transdiagnostic feature of psychological disorders, rumination is associated with slower treatment response, slower rates of recovery, and higher rates of relapse. Accordingly, research has focused on the development of interventions to alleviate rumination. Recently, transcranial Direct Current Stimulation (tDCS) has emerged as a promising tool to do so. Yet, study-to-study variations in stimulation and research protocols preclude a comprehensive understanding of the impact of tDCS on rumination.Methods: We performed a systematic review of sham-controlled tDCS studies targeting rumination among healthy participants or patients with psychiatric disorders, to investigate the effectiveness of tDCS in reducing rumination, and identifying the most desirable combination of stimulation parameters and research protocols to do so.Results: Five out of the nine studies included found a significant effect of tDCS on rumination. However, heterogeneity in results and study designs preclude any definite statement about the impact of tDCS on rumination. Methodological caveats were discussed, and some guidelines for future studies were established.Conclusion: Transcranial Direct Current Stimulation is a promising therapeutic tool to modify transdiagnostic mechanisms like rumination. However, the field needs more extensive and continuous efforts to improve the current methodological caveats and study limitations. This systematic review identifies the existing literature's strengths and weaknesses, providing valuable insights for future efforts.

Excessive Worrying as a Central Feature of Anxiety during the First COVID-19 Lockdown-Phase in Belgium: Insights from a Network Approach

“…Note that, independently from the present study, current clinical research efforts for developing an evidence-based approach for prevention and treatment of the pandemic's mental consequences have likewise pointed to worries as the top-priority clinical target (e.g., Wahlund et al, 2021). Practitioners may also want to capitalize on previous research efforts to develop clinical interventions for worries and related phenomena (e.g., Heeren & Philippot, 2011;Hoebeke et al, 2021;Newman et al, 2011).…”

Transcranial Direct Current Stimulation (tDCS) for Memory Enhancement

“…The tDCS research field is highly heterogeneous regarding methods and measures, thus it is important to clearly report all aspects of the tDCS procedure, including blinding procedure and assessment; the headpositioning of the target as well as the position of the return electrode; the size and shape of the electrodes; type of conducting substance used (saline or gel); the current intensity (mA) and density (mA/cm 2 ) as well as the duration of fade-in/out period; the impedance levels if measured; the duration of the stimulation (including the fade-in/out period); the detailed account of the activities participants were engaged in during the stimulation; the timing and the duration of the cognitive tasks following the stimulation (including break-times, if any). This type of information facilitates standardization and systematic analysis of the published studies (see recent review for example51 ). The aspects that are rarely reported on are the effect of potentially moderating/confounding variables such as time of the day of tDCS session, level of tiredness/mood reported by the participants, successfulness of blinding (i.e., beliefs about the type of stimulation they are receiving), the order of experimental sessions in within-subject designs, etc.…”