Epidemiology of anorexia nervosa in a defined region of Switzerland.

The authors conducted a retrospective study of the incidence of anorexia nervosa in the industrialized canton of Zurich, Switzerland, during three randomly selected sampling periods from 1956 to 1975. The data were derived from case histories from nearly all medical, pediatric, and psychiatric clinics in this region. The incidence of anorexia nervosa increased significantly, from .38/100,000 for 1956-1958 to .55/100,000 for 1963-1965 to 1.12/100,000 for 1973-1975. This increase was not due to the fact that nowadays anorectic patients are hospitalized earlier or that they are hospitalized for less severe illness.