Bifrontal and bioccipital transcranial direct current stimulation (tDCS) does not induce mood changes in healthy volunteers: A placebo controlled study

Transcranial direct current stimulation (tDCS) is the application of a weak electrical direct current (1.5 mA), which has the ability to modulate spontaneous firing rates of the cortical neurons by depolarizing or hyperpolarizing the neural resting membrane potential. tDCS in patients with depressive disorders has been proven to be an interesting therapeutic method potentially influencing pathologic mood states. Except one study, no alterations in mood could be confirmed applying tDCS in healthy participants. In this study, bifrontal or bioccipital stimulation was applied in 17 healthy subjects during 20 minutes with 1.5 mA in a placebo-controlled manner. Bifrontal stimulation consisted of both anodal and cathodal placement on right and left dorsolateral prefrontal cortex (DLPFC) in two separate sessions. Using a set of self-reported moodscales (SUDS, POMS-32, PANAS, BISBAS) no significant mood changes could be observed, neither with bifrontal nor bioccipital tDCS. As already demonstrated by previous studies, we confirmed the minimal side effects and the safety of this neuromodulation technique.