Symptom assessment in casenotes and the clinical diagnosis of schizophrenia

It is well known from several international studies that the incidence rates for schizophrenia, based on first-admission samples, are low in Denmark, especially in females, compared with other countries. This might be due to special diagnostic traditions in Denmark. To analyze how Danish psychiatrists reach a diagnosis of schizophrenia, a stratified subsample of 122 cases out of all 1,259 patients, aged between 12 and 64 years, with a first hospital admission in 1976 under the diagnosis of schizophrenia, paranoid psychosis, acute reactive paranoid psychosis, or casus limitaris was selected. For this subsample, psychopathological symptoms, as documented in the clinical casenotes, were rated by PSE-9 symptom lists for subsequent CATEGO analysis. The core syndrome of schizophrenia, as defined by the CATEGO class S+, showed no association with the clinical schizophrenia diagnosis compared with the other diagnoses mentioned. Also, positive symptoms of schizophrenia did not determine the diagnosis, but for typical negative symptoms such associations were indicated. Some negative symptoms also seemed to be linked to a depressive state. Furthermore, the present work indicates that using first-admission data leads to a higher age at schizophrenia onset and a lower first-admission rate in Denmark compared with Germany.