Validity of the diagnosis schizophrenia in a psychiatric inpatient register: A retrospective application of DSM-III criteria on ICD-8 diagnoses in Stockholm county

In order to assess the quality of the Stockholm county inpatient register for use in epidemiological studies on schizophrenia, a retrospective validity study was performed on a 10% sample of all patients discharged with the diagnosis schizophrenia from hospitals in Stockholm county during 1971. In order to assess fulfillment of the DSM-III criteria for schizophrenia, 102 medical records with an ICD-8 diagnosis of schizophrenia were scrutinized. Seventy-eight patients (76%) were classified as positively fulfilling the DSM-III criteria. In a global assessment, taking into account a lack of documentation on some criteria, 85 patients (83%) were judged as fulfilling the DSM-III criteria for schizophrenia. Excluding the ICD-8 schizo-affective subgroup, 88% of the patients fulfilled the DSM-III criteria for schizophrenia. The DSM-III schizophrenia criteria seem to fit the Swedish diagnostic tradition, except for the age limit of 45 years which excluded 36% of the paranoid group. The study confirms that the ICD diagnosis schizophrenia has been applied with great restriction in Sweden. The validity of the Stockholm county inpatient register as regards the diagnosis schizophrenia is thus quite satisfactory for epidemiological studies on schizophrenia.