[First-episodes psychosis: clinical and epidemiological news].

In the context of the development of early intervention for first-episode psychosis, this manuscript reviews new data with respect to its incidence, risk factors and evolution. Annual incidence of non-affective psychosis appeared to be between 14 and 30/100,000 in people aged 18-64. Incidence decreases with age and is twice higher in men than in women. There is an interaction between age and gender; the risk of psychosis decreases with age faster in men than in women. Thus, for schizophrenia, incidence rate is twice higher in men under 45 year-old and similar in both genders after. There is evidence that genetic and environmental factors may cause enduring liability to psychotic disorder, and, in addition, that genes and environment may interact synergistically. Some environmental factors have been identified; they concern foetal life, childhood or adolescence and may be conceptualized at the individual or the contextual level. The definition of recent onset psychosis may be based on duration of psychosis, between two and five years. Its development is identified through the occurrence of major psychotic symptoms, such as positive, negative symptomatology or disorganization, and impairment of social functioning. The types and patterns of occurrence and of evolution of psychotic symptoms have a prognostic impact. A long duration of untreated psychosis impacts symptomatology. It is associated with less severe positive symptoms at baseline and more severe after three years, insidious onset, male gender, early onset, and diagnosis of schizophrenia. Recent onset psychosis is often associated with comorbidities, such as depression, anxiety disorders, suicidal behaviours, and addiction. Symptomatic remission rates are found between 25 and 60%. Symptomatic and functional remissions favour each other. A third to half of patients is active, employed or students. Symptoms and evolution are various in studies, probably corresponding to various patho-physiological mechanisms.