A Negative Pilot Study of Daily Bimodal Transcranial Direct Current Stimulation in Schizophrenia

Background: A small number of studies conducted to date have suggested that transcranial direct current stimulation (tDCS) applied to the temporoparietal cortex may reduce auditory hallucinations in patients with schizophrenia. Prefrontal brain stimulation with other methods, has also been shown to potentially improve the negative symptoms of this disorder. Objective: To investigate the therapeutic potential of daily bimodal tDCS: anodal stimulation to the prefrontal cortex and cathodal stimulation to the temporoparietal junction in patients with persistent hallucinations and negative symptoms of schizophrenia. Methods: We conducted two small randomized double-blind controlled trials comparing bimodal tDCS to sham stimulation. In one study, stimulation was provided unilaterally, in the second study it was provided bilaterally. Results: Neither unilateral nor bilateral tDCS resulted in a substantial change in either hallucinations or negative symptoms. Stimulation was well tolerated without side-effects. Conclusion: Daily tDCS does not appear to have substantial potential in the treatment of hallucinations or negative symptoms and further research should investigate higher doses of stimulation or more frequently applied treatment schedules. (C) 2014 Elsevier Inc. All rights reserved.