The Epidemiology of Severe Mental Retardation in Sweden

To facilitate comparative studies in future epidemiological research, a summary of the available epidemiological and etiological data on severely mentally retarded children from some demographically different areas in Sweden (Gustavson, Hagberg, Hagberg, & Sars, 1977a, b; Gustavson, Holmgren, Jonsell, & Bromquist, 1977c) may be of interest. The children concerned were born in the period 1959-1970, that is, just before the gradual introduction in Sweden of prenatal diagnosis and other measures to prevent congenital disorders and during a period when there was a decrease in perinatal mortality.