Schizophrenia is the most severe form of psychosis. This chronic illness sees acute phases (including delirium, hallucinations, disorganised behaviour, etc.) alternate with milder phases, during which the person’s perception of reality and personal, social and professional situations are not as severely compromised.

Generally, this disorder arises in late adolescence or early adulthood. In the early stages, it is often misdiagnosed and may be confused with a depressive episode or a “teenage crisis”. Symptoms must last more than one month.  
We differentiate between a short-term psychotic disorder (which lasts less than a month) and schizophreniform disorder, when the duration is more than 1 month but less than 6.