Repeated transcranial direct current stimulation (tDCS) in nondepressed reduces levels of reported negative affects from daily stressors

TL;DR

Repeated bilateral prefrontal tDCS in nondepressed individuals reliably reduces negative affect from daily stressors, with effects observable after just three days of treatment, suggesting a potential non-pharmacological approach to mood regulation.

Contribution

This study demonstrates that short-term, repeated bilateral prefrontal tDCS can effectively decrease negative emotional responses in healthy individuals, expanding its potential applications beyond clinical depression.

Findings

tDCS reduces negative affect in nondepressed individuals

Effects observed after 3 days of stimulation

Replicated findings in independent experiment

Abstract

Negative emotional responses to the daily life stresses have cumulative effects which, in turn, impose wide-ranging negative constraints on emotional well being and neurocognitive performance (Kalueff:2007cp, Charles:2013eq, Nadler:2010hk). Crucial cognitive functions such as memory and problem solving, as well more short term emotional responses (e.g., anticipation of- and response to- monetary rewards or losses) are influenced by mood. The negative impact of these behavioural responses is felt at the individual level, but it also imposes major economic burden on modern healthcare systems. Although much research have been undertaken to understand the underlying mechanisms of depressed mood and design efficient treatment pathways, comparatively little was done to characterize mood modulations that remain within the boundaries of a healthy mental functioning. In one placebo-controlled experiments, we applied daily prefrontal transcranial Direct Current Stimulation (tDCS) at five points in time, and found reliable improvements on self-reported mood evaluation. We replicated this finding in an independent double-blinded placebo-controlled experiment and showed that stimulation over a shorter period of time (3 days) is sufficient to create detectable mood improvements. Taken together, our data show that repeated bilateral prefrontal tDCS can reduce psychological distress in nondepressed individuals.