The validity of schizophrenia diagnosis in the Finnish Hospital Discharge Register: Findings from a 10-year birth cohort sample

The purpose of this study was to investigate the diagnostic validity of schizophrenia in the Finnish Hospital Discharge Register (FHDR) with a large, epidemiologically representative sample using a multidiagnostic approach (DSM-III-R, DSM-IV, ICD-10), and to find additional criteria that could be used to improve the validity of schizophrenia diagnosis in future register-based research that utilizes the FHDR. The study population consisted of all individuals (n=877) who were born in Helsinki, Finland, between 1 January 1951 and 31 December 1960, and who had had at least one diagnosis of schizophrenia, schizophreniform disorder or schizoaffective disorder in the FHDR. All their available hospital case notes were collected. The total number of subjects for whom case notes were obtained was 806. We used the OPCRIT system (version 3.4) to produce diagnoses according to ICD-10, DSM-III-R and DSM-IV criteria based on the information extracted from the hospital case notes. We examined the distribution of the DSM-...