Regional differences in schizophrenia incidence in Denmark

OBJECTIVE: To examine the regional distribution of schizophrenia incidence in Denmark. METHOD: A cohort consisting of 2441 Danish psychiatric patients, with first-time admissions between January 1, 1978 and December 31, 1982, and diagnosed as having schizophrenia (ICD-8) at least once in a 10-year period of observation was divided into three regional groups by degree of urbanization. RESULTS: Incidence increased for both sexes with increasing urbanization. A diagnostic delay was most pronounced in the least urbanized areas and was most pronounced for women. CONCLUSION: Our study confirms the existence of regional differences in schizophrenia incidence on a national basis. Marked regional differences in diagnostic delay were also demonstrated. A possible explanation could be regional differences in diagnostic procedures, underlining the importance of uniform diagnostic patterns as a means for reliable mapping of psychiatric morbidity and, hopefully, adequate treatment.