Transcranial Direct Current Stimulation (tDCS) in Treatment-resistant Depression

tDCS applies a small amount of direct electric current (DC) to the brain by means of two electrodes: the one is an active electrode, localized on the effective site, and the other is a reference electrode, localized on some "silent" part of the body. Anodal transcranial direct current stimulation (tDCS) of the left dorsolateral prefrontal cortex (DLPFC) has been associated with working memory enhancement and improvement of mood. This study will investigate the possible antidepressant effects of tDCS in patients with therapy resistant major depressive episodes.

Transcranial direct current stimulation (tDCS) is a non-invasive method that shifts membrane potential towards hypo- or hyperpolarization and therefore leads to functional changes in a discrete area of the cerebral cortex. Neurophysiological studies have shown that slow changes in cortical scalp potential reflect overall activity of cortical neuronal networks. These scalp potentials reflect shifts in membrane potentials of the cortical neurons. Over the past 7 years tDCS has evolved as an important tool to non-invasively manipulate specific neural circuits of the human brain. The purpose of this study is an investigation of tDCS applied to 20 therapy-resistance major depressive patients. Our hypothesis is that tDCS may exert an antidepressant effect and/or enhances the medication effect. tDCS will be examined in the framework of a placebo-controlled clinical pilot-study investigating effectiveness, safety and influence on EEG parameters. Patients will receive anodal DC stimulation or sham stimulation (extra designed placebo-stimulator) in a double-blind design over 10 days for each condition. Outcomes will be evaluated using several clinical, psychiatric and neuropsychological rating scales.