Influence of Environmental Factors on the Prevalence, Risk and the Clinical Manifestations of Schizophrenia

Schizophrenia is a chronic and severe mental disorder with a lifetime prevalence of about 1 per cent, the symptoms can be very disabling and causing a heavy medical and socioeconomic.

There are significant variations from one population to another. Clinical manifestations of schizophrenia (symptoms, evolution, severity of disability) are highly variable. This variability, both epidemiological and clinical, is due to genetic and environmental factors.

Environmental factors may be either risk factors or modifying factors (changing clinical presentation but do not alter the risk of disease) for schizophrenia.

Environmental risk factors have been identified (eg: urbanity, cannabis, migration), but the investigators don't know neither the components directly responsible, nor the mechanisms by which they increase the risk of schizophrenia.

To date, there is no study has systematically evaluated the role of environmental modifying factors in schizophrenia.

Environmental factors may be individual, unique to each person (eg cannabis, migration.), or population-based (eg ethnic density, socio-economic difficulties.) The identification/ identifying of environmental risk factors or modifiers, both individual and population, may have theoretical implications (understanding of etiopathogenic mechanisms) and practical (implementation of preventive measures). The potential effectiveness of preventive measures is even greater than the risk attributable to certain environmental factors is important.

Most studies on environmental factors in schizophrenia were conducted in Anglo-Saxon countries and northern Europe, but no study of these risk factors has been conducted in France.

There are important differences environment based on study populations, these results are not generalizable to other countries, including France.