One of the investigators went abroad

Social cognition concerns the understanding of how people think about others and how that, in turn, influences our behavior, feelings, and social interactions. schizophrenia social-cognitive impairment is profound (effect size D>1.2), medication resistant and critically limits functional well-being . Social cognition involves complex patterns of coordinated activity within numerous cortical and subcortical networks, making it a difficult target for clinical neuroscience investigation. Yet, prior research demonstrates that sensory-perceptual dysfunction in schizophrenia can upwardly generalize into higher-order social-cognitive impairment making perception a tractable and fruitful approach for studying social cognition in schizophrenia. Here, the investigators explore how distortions in perception of temporal coincidence can contribute to the aberrant inferences of physical causation and social agency.

Social cognitive deficits in these patients are robust and hinder their ability to maintain gainful employment as well as forge and sustain meaningful social relationships. Current antipsychotic medications are largely ineffective in treating these symptoms. The proposed protocol aims at utilizing Noninvasive Brain Stimulation (NIBS) and cognitive behavioral training to enhance core perceptual impairment in marking time that may contribute to both social and nonsocial cognitive dysfunction in schizophrenia.

Cognitive behavioral training along the line investigators propose has no reported adverse effects.The transdirect current stimulation (tDCS) is a very safe method with encouraging results in previous works in which no severe adverse events where found. There are a few minor side effects including skin irritation, a phosphene at the start of stimulation, nausea, headache, dizziness, and itching under the electrode. A recent study of over 500 subjects using the currently accepted protocol reported only a slight skin irritation and a phosphene as side effects. Patients can benefit from a significant improvement of invalidant symptoms but also of their quality of life. To ensure safety, patients will be accompanied throughout the protocol by professionals trained in the management of their disease. Besides the protocol procedure, patients will be supported, in all centers, according to the international recommendations in terms of safety and practice. Patients receiving placebo procedure after randomization will pursue pharmacological treatment and usual health care.

Inclusion Criteria:

• be between 18 and 45-years-old
• have normal hearing assessed by the Five-minute hearing test
• have French as a first language
• be able to provide written informed consent
• be right handed as measured by the Edinburgh handedness scale
• covered by, or having the right to Social Security
• informed consent signed
• patients with diagnosis of schizoprenia or schizoaffective disorder-depressive type as determined by the SCID Diagnostic Interview for DSM-V and administered by a clinician
• clinically stable and on a stable medication regiment for the past 3 months

Exclusion Criteria:

• significant medical or neurological illness or history of fetal alcohol exposure that may increase risks of the study, significantly affect brain function, or impede participation
• substance dependence (except nicotine) or abuse not in remission within the past six months or recent use presenting the possibility of acute intoxication or withdrawal
• a history of any Axis I psychiatric disorder except those required in the inclusion criteria, any history of pervasive developmental disorder or mental retardation
• for Visit 3: If participating in tCDS Contraindications for tDCS (pacemaker or brain stimulator) and/or MRI (neurologic stimulator, pacemaker, cardiac defibrillator, cardiac prosthesis, vascular prosthesis, intracranial clips or clamps, cerebrospinal fluid derivation, metallic splinters in the eyes)
• patients under curatorship/guardianship and whose clinical condition requires inpatient procedure under constraint
• healthy controls must not be currently using psychoactive médications or have a first-degree relative with a psychotic disorder