The regions which are assumed to underlie the pathophysiology of schizophrenia, namely hypoactivity at the prefrontal level and pathological hyperactivity of the associative regions of the language located in the left temporoparietal region.

To assess the efficacy of tDCS on auditory hallucinations, the investigators performs an randomized double blind versus placebo trial. In each arms patients will receive two tDCS sessions a day during two weeks.

Hearing hallucinations are one of the major symptoms of schizophrenia. In 30% of patients they are resistant to common psychotropic treatments. tDCS (Transcranial Direct Current Stimulation) is a technical of brain stimulation, non-invasive, painless that modulates brain activity by the transcranial administration of a low-intensity electric current, via two electrodes (an anode and a cathode). Several scientifics studies have reported a beneficial effect of tDCS in the treatment of pain, depression and especially hearing hallucinations in schizophrenia.

The main study purpose is to evaluate the effectiveness of tDCS on resistant auditory hallucinations in patients with schizophrenia.

Then, to evaluate the effectiveness of tDCS on global schizophrenic symptomatology and to assess the impact of tDCS on patients' quality of life.

Also the study, evaluate the impact of tDCS on cortical excitability. We measure the change in serum BDNF (Brain Derived Neutrophic Factor) before and after tDCS stimulation. Indeed, to evaluate the impact of tDCS on neurocognitive functions.

Patients will receive either active tDCS or placebo tDCS randomly. All patients will have two tDCS/day sessions, one hour apart, for 2 working weeks. The stimulation parameters will be consistent with the literature data, namely: Intensity = 2mA; duration of sessions = 20 minutes; total number of sessions = 20 (2 daily sessions for two working weeks).

Inclusion Criteria:

• Schizophrenia according to DSM-V.
• Refractory auditory hallucinations(despite two antipsychotics trials).
• Right-handed patients.
• Written informed consent.

Exclusion Criteria:

• Presence of other psychiatric disorders than schizophrenia (except addiction to tobacco or caffeine ).
• History of severe head trauma or coma.
• History of epilepsy or neurological disorder or a general medical condition.
• Presence of intracranial metallic objects or pacemaker.
• Hospitalized patients without consent.
• pregnant women .