Evaluation of the Efficacy of Immunomodulatory Therapy in Case of Psychiatric Disorders With Proven Dysimmunity.

Inclusion Criteria: * For Adult: First acute or relapse of psychotic disorders defined by the BPRS-E scale with or without standard pharmacological treatment. * For Children: Child over 6 years old with a first acute or relapse of psychotic disorders defined by the Kiddie sads-PL scale with or without standard pharmacological treatment. * Biological diagnosis of pathogenic CNS autoantibodies in the blood. * MDC scale score \>3 is required for inclusion in step 2. * Normal ECG in case of previous heart disease. * Informed consent of the patient or his legal representatives. * Effective contraception for women of childbearing potential during the study and for at least 12 months after the last rituximab administration. Exclusion Criteria: * Developmental disorder related to a genetic disease. * Co-existing disorder of severe neurological disease. * Chronic psychotic disorders receiving ongoing neuroleptic treatment with efficacy. * Hypersensitivity to the active substance (rituximab) or to murine proteins, or to any of the other excipients * Blood platelets \< 75x109/L * Neutrophils \< 1.5x109/L * Neoplastic pathology, * Hepatitis B or HIV infection, * Contraindication to immunosuppressant treatment (active severe infection, severely immunocompromised state). * Severe heart failure (New York Heart Association Class IV) or severe, uncontrolled cardiac disease * Pregnant or breastfeeding women * Currently receiving an investigational drug or received an investigational drug or device within 30 days (or 5 half-lives for drugs, whichever is longer) prior to screening. * Previous treatment with rituximab in the past 12 months. * Patients with a history of recurring or chronic infections or with underlying conditions which may further predispose them to serious infection (e.g. hypogammaglobulinemia). * Recent vaccination with live viral vaccine (within 3 months). * Any other medical illness or disability that, in the opinion of the investigator, would compromise effective trial participation.