Objectives. Exploration of trends in the prevalence of long-term inpatient care provision to the mentally retarded and an attempt at explanation of territorial differentiation in this respect.
Method. The following three subgroups were surveyed in the population of the mentally retarded in consecutive years: mental hospital inpatients with at least one-year hospital stay, residents of nursing homes (DPS) registered there at the end of year, and those staying at the end of year in long-term residential care/treatment facilities (ZOL). Four independent variables were taken into account in the analysis of causes of territorial differentiation; in the correlational analysis the Spearman rho coefficient was used.
Results. Mental retardation prevalence in the population of children and adolescents has systematically decreased in the years 1992-2005, from 38 to 22 per 100 000population. In the adult population the rates have decreased only slightly, from 76 to 74. A considerable territorial differentiation in the prevalence rates was found: in the children's population the highest rates were 4.5 times higher than the lowest ones, while in the adult population the difference was almost threefold. The prevalence rates were not related either to the accessibility of community self-help facilities or the size of rural population in the province, but were associated to some extent with the economic situation in the region.
Conclusions. Over the 14 years under study the prevalence of mental retardation among children and adolescents has decreased by 42%o, and remained rather stable in the adult population. The prevalence rates were relatively the lowest in the provinces of Lodz and Silesia, and the highest in the Opole and Warmian-Masurian provinces. The territorial differentiation depends to some extent on the economic situation of a given province inhabitants.