Dimensional and Developmental Profiles of Psychosis in Children and Adolescents

Inclusion Criteria for the Patient: 1. Children and young adults ages 7-20 years with age of onset of psychotic disorder between 7-17 years. 2. Hospitalized or seen for out-patient treatment for a psychotic episode, acute or chronic. 3. DSM-V diagnosis of schizophrenia, schizoaffective disorder, schizophreniform disorder, brief psychotic disorder, psychotic disorder not otherwise specified, or major depressive episode with psychotic features. 4. Written informed consent signed by the parents or the individual(s) with legal parental authority, and by the minor patient if his/her condition permits. 5. Written informed consent signed by the patient if he/she is a major, after clinical stabilization (not delusional). 6. Has health insurance coverage from Social Security (France) (not AME coverage). Inclusion Criteria for parents or siblings wishing to participate in the genetic part of the study : 1. Parents : no specific criteria. 2. Siblings : siblings are eligible to participate if there are at least two first-degree relatives with psychotic disorders (including the patient) in the family. 3. Written informed consent for the genetic part of the study signed by any participating parents and siblings. 4. Has health insurance coverage from Social Security (France) (not AME coverage). Exclusion Criteria: 1. Moderate or severe intellectual deficiency (IQ \< 50). 2. Psychoses judged to be secondary to medical illness, medication effects or drugs of abuse. 3. Diagnosis of bipolar disorder. 4. Patients who are under legal guardianship. 5. For the neuroimaging part of the study only : any contraindications to Magnetic Resonance Imaging.