[Psychiatric epidemiology: demographic study and characterization and prevalence rate of mental diseases]

The authors report an experience on the assessment of mental illness prevalence rate in the socio-professional population of four French provinces. This analysis, preceded by a demographic study of the considered population, will be extended by an incidence of mental disorders research relative to constitute a cohort of patients which 3 years follow-up study will allowed to make a cost analysis (cost-effectiveness) of the chosen therapeutic ways and means.