Increasing incidence of borderline states in Denmark from 1970-1985.

In Denmark sex and age standardized rates of first-admission diagnosis of the borderline state (301.83; ICD-8), have significantly increased during the 16 year interval 1970-85. There was no increase in the sex and age standardized rates of first-admission diagnosis of the other borderline state schizophrenia latens (295.59; ICD-8), in the same period. There was not sex difference in application of the 301.83 diagnosis, but a generation effect, the age group 15-34 especially contributed to the increase. Analysis of the geographic variation showed a five-fold relative risk of receiving the 301.83 diagnosis in the metropolitan area of Copenhagen compared with a total of three selected counties. Possible causes of the increase are discussed. There is every probability that the increase is due to change in diagnostic habits, but change in population psychiatric morbidity can not be excluded.