Rationale: Auditory hallucinations (AH) are a symptom of several psychiatric disorders, such as schizophrenia. In the majority of patients, these AH respond well to antipsychotic medication. Yet, a significant minority continues to experience frequent AH despite optimal pharmacotherapy and AH severely decrease quality of life in these patients. The number of alternative treatment options for this medication resistant group is currently low and most of them focus on coping with the hallucinations. Transcranial direct current stimulation (tDCS), in contrast, is a safe, non-invasive technique that is able to directly influence cortical excitability through the application of very low electric currents. This technique has only a few transient side-effects and is cheap and portable. To date, only one randomized controlled trial has been published, suggesting high efficacy of tDCS for the treatment of medication-resistant AH in a relatively small sample. We aim to replicate and extend these findings by investigating the efficacy of this technique in a larger sample.
