Treatment of major depression with transcranial direct current stimulation.

Various forms of brain stimulation appear to be effective in the treatment of depression. Eletroconvulsive therapy (ECT) is the most effective treatment of depression available, but it is associated with anesthetic risks, adverse cognitive effects, and social burden. The advent of repetitive transcranial magnetic stimulation (rTMS) offers a less invasive option for depression treatment. However, rTMS is still expensive and the results are heterogeneous (1). Deep brain stimulation and vagal nerve stimulation are being studied as potentially promising depression treatments, but both are invasive. In recent years, a brain stimulation technique that seemed long forgotten has received renewed attention: the transcranial stimulation with weak direct currents (transcranical direct current stimulation). There are few past reports of tDCS to treat depression (2). However, at the time of those trials much less was known about methodological aspects and physiologic effects of tDCS and the results were quite variable. It is now clear that the efficacy of tDCS depends critically on parameters like electrode position and current strength (3). Furthermore, important advances in the understanding of depression pathophysiology, such as neuroimaging studies showing a focal frontal dysfunction in brain activity, suggest that a focal technique of brain stimulation might be helpful for the treatment of depression (4). Therefore, based on these recent evidences, studies re-evaluating the effects of tDCS on depressed patients are warranted. In this randomized, controlled and double-blind trial, we investigate the effects of 5 days of anodal stimulation of the left dorsolateral prefrontal cortex in 10 patients with major depression (42.7 ± 10 years). Patients were randomly assigned into one of two groups: active or sham tDCS. All patients were evaluated by the same rater, who remained blinded to the results of the study group assignment. tDCS was applied through a saline-soaked pair of surface sponge electrodes (35 cm). The anode electrode was placed over F3 (10–20 International EEG System) of each subject. The cathode was placed over the contralateral supraorbital area. A constant current of 1 mA strength was applied for 20 min/day (administered for five alternated days). For sham stimulation, the stimulator was turned off after a few seconds. All patients tolerated tDCS without complications. At the end of treatment, there were four treatment responders in the active group versus no responders in the sham group. The patients that received active stimulation had a significant decrease in the Hamilton Depression Rating Scale and Beck Depression Inventory scores when compared with baseline that was not observed in patients that received sham stimulation (Fig. 1).